Quiet urban air delivery system

ABSTRACT

A public transportation system combines a unique combination of components that includes interoperable electric-powered vehicles, facilities, hardware and software having specifications, standards, processes, capabilities, nomenclature, and concepts of operations that together include a concerted, comprehensive, multi-modal, future system for moving people and goods that is herein named Quiet Urban Air Delivery (QUAD) and in which uniquely-capable, ultra-quiet, one to six-seat, electrically-powered, autonomous aircraft (SkyQarts) fly sub-193 kilometer trips on precise trajectories with negligible control latency and perform extremely short take-offs and landings (ESTOL) with curved traffic patterns at a highly-distributed network of very small, airports (“SkyNests”) that themselves have standardized compatible facilities that interoperate with SkyQarts as well as with versatile, autonomous electric-powered payload carts (EPCs) and robotic delivery carts (RDCs) to provide safe, fast, on-demand, community-acceptable, environmentally friendly, high-capacity, affordable door-to-door delivery of both passengers and cargo across urban, suburban and rural settings across the globe.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation in part of U.S. application No.17,266,451, filed on Feb. 5, 2021, and currently pending, which is anational stage application of PCT application No. PCT/US2020/045686,filed on Aug. 11, 2020 and currently pending, the entirety of bothapplications are hereby incorporated by reference herein.

BACKGROUND OF THE INVENTION Field of the Invention

The present invention is comprised of a public transportation systemconsisting of a unique combination of components that includesinteroperable electric-powered vehicles, facilities, hardware andsoftware along with their range of specifications, standards, processes,capabilities, nomenclature, and concepts of operations that togethercomprise a concerted, comprehensive, multi-modal, future system formoving people and goods that is hereby named Quiet Urban Air Delivery(QUAD) and in which uniquely-capable, ultra-quiet, one to six-seat,electrically-powered, autonomous robotic aircraft (“SkyQarts”) can flysub-193 km trips on precise trajectories with negligible control latencyand perform extremely short take-offs and landings (ESTOL) with curvedtraffic patterns at a highly-distributed network of very small, airports(“SkyNests”) that themselves have standardized compatible facilities, asdefined herein, that interoperate with SkyQarts as well as withversatile, autonomous robotic electric-powered payload carts (EPCs) andelectric-powered autonomous robotic delivery carts (RDCs) to providesafe, fast, on-demand, community-acceptable, environmentally friendly,high-capacity, affordable door-to-door delivery of both passengers andcargo across urban, suburban and rural settings in both developed andundeveloped countries across the globe.

Background

The surface transportation system in urban regions of the USA in 2019 isfraught with ever-worsening traffic congestion that entails enormousamounts of wasted time and fuel, high levels of greenhouse gas emissionsas well as unsustainable infrastructure costs. US Department ofTransportation (DOT) data show that these ills are worsening each yearand appear headed for an untenable future. The waiting time betweenbuses and trains and their sparse destinations have caused the ridershipon public transit to remain at around 5% for the last four decades,making it insufficient to solve transportation's ills. The recentpandemic and the concern about acquiring infectious disease from otherpassengers has reduced ridership on public transit even further. Thegrowing demand for expeditious same day delivery by the US PostalService, UPS, FedEx, Amazon and other shippers of important andessential supplies, food, parts, equipment and documents cannot be metdue to transportation's ills. Commercial airline service has similarlimitations. Valiant efforts to stimulate shared public transportationhave not solved the problem of surface congestion. Public rail transitis inherently very limited in its number of destinations and itsinfrastructure is very expensive to build. It typically requires faresubsidies in order to win meaningful levels of ridership. Gridlockedfreeways compel recurring expenditures to acquire more land on which tobuild more freeway lanes, at enormous expense and with no apparent endto the need for such expansion.

SUMMARY OF THE INVENTION

This invention comprises a system. A system is a collection ofcomponents that are organized for a common purpose. Systems rely uponeach of their components to fulfill its important role to make thesystem work. Such components may have little or no meaning or value asstand-alone items; only when combined and integrated into a system dosuch components become valuable. For example, a keyboard alone without acomputer and monitor has little or no value.

A recent convergence of technologies, including the development of moreadvanced energy storage devices and driverless electric cars, along withthe ever-worsening surface gridlock in metropolitan areas has opened thepossibility for a new, multi-modal type of public transportation systemthat uses autonomous robotic electric-powered, low-emissions air andland vehicles to provide trips across distances of up to 220 km withmany trips as short as 16 km (10 miles) or less across urban, suburbanand rural areas to and from very small airports that have high proximityto where people live and work. To be publicly acceptable and to succeedin achieving mass transportation volumes, these air vehicles need to beultra-quiet, safe, easy to board and able to efficiently transport oneto six passengers for hire while operating expeditiously with negligiblecontrol latency on precise trajectories and with extremely shorttake-offs and landings (ESTOL) at a highly-distributed network of verysmall, high-proximity, specially equipped airparks (SkyNests). No extanttransportation system can fulfill all of these requirements. Thenecessary aircraft are enabled by the emergence of new, high-energydensity batteries, ultra-quiet propellers and driverless vehicletechnologies, which enable them to combine ultra-quiet electricpropulsion, reduced emissions and adequate range with highly agile,precisely controlled flight and ground operations. These ultra-quiet,electric-powered aircraft are herein named SkyQarts and they are of aspecialized new unique design that fulfills a uniform set of standardsfor consistent ESTOL performance, operational capabilities and size. TheSkyQarts as embodied herein are fixed-wing ESTOL aircraft, butalternative embodiments may be vertical take-off and landing (VTOL) withtilt-wing, tilt rotor or wingless multi-rotor aircraft.

Throughout this disclosure, the word “autonomous” means a vehicle ormachine that is driverless and sentient of position, destination andobstacles and that is navigated and maneuvered by a computer without aneed for human control or intervention

The word “robotic” as used herein means a vehicle or machine that isable to receive and perform commands or instructions, whether by humanoperated joystick or by autonomous capability.

It is noteworthy that all electric air and land vehicles describedherein are both robotic and autonomous. They are robotic in that theyperform the commands of a networked situational awareness system and aprecision positioning system, such as where to go, where exactly to dockand when. They are autonomous in being sentient of position, destinationand obstacles and able by their on-board computerized autonomous controlsystem to self-navigate and maneuver past traffic and obstacles whenenroute to their destinations.

All SkyQarts are uniquely capable of being precisely positioned andrapidly loaded and unloaded, in as little as 20 seconds, at a dock'saircraft service bay using standardized, pre-loaded, robotic autonomouselectric-powered payload carts (EPCs). The autonomous robotic EPC is aninnovation that enables one of this invention's several key components.The EPC saves time by reducing mode changes and prep-delays. The EPC iscapable of hauling a variety of payloads including both people andgoods, and it is designed to be carried not just inside the axisymmetricfuselage pod of the SkyQart aircraft, but also with a piggybacktransportation function atop specially designed compatibleelectric-powered autonomous robotic delivery carts (RDCs), as well asatop or inside other vehicles such as small cars, pick-up trucks andcommercial trucks. The RDC is also one of this invention's several keycomponents. This combination of SkyNests, SkyNest docks, SkyQarts, EPCs,RDCs and the other components enumerated herein are expressly designedto comply with standards that allow them to interoperate as amulti-modal system of rapid delivery of people and goods from departingdoorstep to destination doorstep. This new, aviation-based system offerswhat no extant transportation system can, i.e., quiet, safe, fast,zero-tail-pipe emissions, on-demand, multi-modal mass transportation andit is herein named the Quiet Urban Air Delivery (QUAD) system. Itsworking matrix of autonomous robotic electric-powered vehicles,facilities, hardware and software along with their range ofspecifications, standards, processes, capabilities, nomenclature, andconcepts of operations together comprise a concerted, comprehensive,multi-modal, on-demand, mass transportation system to transport peopleand goods is the subject of this invention.

The main enabling vehicle for QUAD is its aircraft, the ultra-quiet,electric-powered, extremely short take-off and landing SkyQart. Thenominal interoperable embodiment of the SkyQart presented herein is anautonomous robotic fixed-wing aircraft that is exemplary of anintegrated design that can fulfill the performance requirements of theQUAD system and can be readily and affordably certificated by theFederal Aviation Administration and other regulatory bodies as safe tocarry passengers for hire. This advantage does not exclude the use ofalternative embodiments of the SkyQart, including those that employtilt-wings or tilt-rotor or vertical multi-rotors for VTOL operation, ifthey can be designed to be certificated and compatible with communitynoise requirements as well as with the use of EPCs, RDCs and thecadenced coordinated operations at SkyNests and their docks. Cadencedcoordinated operations require that the EPCs, RDCs and SkyQarts at aSkyNest interoperate both on-time and just-in-time. The nominalinteroperable embodiment of the SkyQart is further distinguished by itsunique combination of several enabling innovations into one aircraft,including the following components: the extremely low drag axisymmetricfuselage pod (AFP) that contains the SkyQart's interior cabin, the cargoaxisymmetric fuselage pod, active main landing gear, ultra-quietpropellers that serve as spoilers, landing gear wheelmotors in its mainlanding gear, retractable nose wheel landing gear, a solenoid-actuatedpin-latching system, a precision positioning system, a standardizedswappable battery pack (SBP) with robotic battery swapping, Qusheat ridecontrol seats, an autonomous control system, an community acceptablenoise sphere, a closed-flotation system, the blown, double-slotted fastflap system, the automatic rear hatch, the peelable window frame foremergency exit, the DC fast-charging port, guided rate accelerationchange execution (GRACE) and the Faraday cage around its battery pack.By virtue of this combination of innovative components, this patent isthe first concerted system that addresses all of the transportationproblems listed in the Background section above and it is the firstaviation-based system designed to do so at meaningful scale. The maximumcapacity of the QUAD system is predicated upon the use of autonomousrobotic electric-powered vehicles, but the system can operate at lowercapacity using human-piloted electric-powered vehicles during itsinitial years of demonstration start-up operations. The QUAD system, byusing virtual highways in the sky, aims to complement the surfacetransportation system by minimizing the need for expensive new pavedroads, bridges, tunnels and parking spaces, while preserving theprevalent personal preference for traveling in a private vehiclecompartment with at least one or two seats.

The safety of the QUAD system is of paramount importance and all of itsvehicles and its operations will ultimately have to comply withapplicable safety regulations as well as with FAA and EASA certificationstandards. Some of those standards will evolve as the QUAD system isimplemented. The goal is to have the QUAD transportation system provide9-sigma safety, meaning an accident rate of one per one billionoperations. The components of the QUAD transportation system andparticularly those of its autonomous robotic SkyQart that are importantto its safety are the following: runway crash cushions, a sentient,ever-vigilant, networked autonomous control system with fusedmulti-sensor see and avoid hardware and software coupled to automatedflight controls with negligible control latency to detect and preventair traffic conflicts and provide aerial agility, a networkedsituational awareness system, a ballistic recovery system consisting ofa vehicular parachute, a closed flotation system for buoyancy in case ofditching in the water, an emergency locator transmitter (ELT), shoulderharnesses with built-in airbags, rescue lift-hooks on airframehardpoints for helicopter rescue of entire vehicle, peelable roundwindow frames as emergency exits on the sides of the AFP, a Faraday cageto limit voltage shock hazard and radio frequency interference leaks, anautomated check-list and self-diagnostics including automatic pre-flightself-inspection before every flight, landing and take-off speeds limitedto no more than 24 m/sec, an automatic fuel gauging and rangeprotection, a fire-proof or fire-resistant materials in the SkyQartairframe, a smoke and carbon monoxide detectors in the SkyQart cabin, anautomatic fire extinguisher system in the SkyQart cabin, a batterymanagement system in all standard battery packs, a fire-proof containerfor all standard battery packs, regularly scheduleddisinfecting/cleaning of SkyQarts, EPCs and RDCs, a nominalinteroperable maximum glide ratio of more than 17:1 and a taxiingSkyQart that can taxi without using a propeller or a rotor. Negligiblecontrol latency is defined herein for the autonomous control systems ofthe electric-powered air and land vehicles described herein as acapability of determining and activating a controlled movement of saidvehicle in less than one second.

A landing indicated airspeed that is limited to no more than 24 m/seccould have alternative embodiments wherein a landing speed is in aconceivable range of about 20 m/sec or more, about 22 m/sec or more,about 26 m/sec or more, about 27 m/sec or more or any value between andincluding the speed values provided, while the preferred range is 21.5m/sec to 27 m/sec and the nominal interoperable landing speed is 24m/sec as this provides a preferred combination of safety, low noise,shortened runway requirements enabling smaller airparks, adequate flightcontrol authority during landing, expeditious airport trafficflow/capacity and sufficient cruise speeds without excessive wing area,susceptibility to flight turbulence or adverse energy efficiency.

It is clear that a new modal solution is urgently needed fortransportation and QUAD proposes to be that solution. The severalcomponents that make QUAD a workable, high-capacity solution areinterdependent because only together can they enable the core missionrequirements and operational requirements of QUAD to be met. Therefore,these components, including said SkyQarts, electric-powered autonomousrobotic delivery carts, autonomous robotic electric payload carts,facilities, processes, operations, components, capabilities,nomenclature and standards that comprise the concerted, interoperable,comprehensive, multi-modal, on-demand future public transportationsystem that is the subject of this invention, herein described andcalled Quiet Urban Air Delivery (QUAD) are together what comprises thisinvention.

A fundamental and recurring principle in this invention is that theseveral components of QUAD are definable, interdependent, interoperableand system-enabling. This principle is valid because the dimensions,performance and energy requirements of human mobility are constrainedwithin definable boundaries by combining the size of humans withimmutable natural and social sciences including physics, humanphysiology, sociology, psychology and economics along with the culture,habits and built-environment of the extant surface transportationsystem. These sciences determine the workable, tolerable and acceptableparameters for a public transportation system in terms of its noiselevel, speeds, accelerations, size, weight, cost, ease-of-use and safetylevel. To be sustainable, the QUAD system must include defined,quantified and uniform standards for these parameters and others in arange that respects those laws of science. Such physics-compatiblestandards are important to achieving mass production, interoperability,parts commonality and economies of scale, all of which help enable asustainable, affordable mass implementation of the QUAD system. For mostparameters there is a magnitude that fulfills the need at a human scalewith the physically correct size, weight, motion or user experience. Themagnitudes of the parameters presented in the embodiments herein are ofa physically correct human scale and are thereby interoperable.

It is important to note the following definitions regarding parameters,as nominal, nominal interoperable, or standard: In order for the QUADsystem to be a transportation system, it follows that several workable,tolerable, interoperable dimensions, weights, forces, rates and otherparameters must be specified in this patent for the embodiments of thevehicles, components and facilities contained herein. Accordingly, thedefinition intended by use herein of the descriptive term “nominal”, isthat definition given by Merriam-Webster “of, being, or relating to adesignated or theoretical size [or magnitude] that may vary from theactual: e.g. approximate”. The descriptive term “nominal interoperable”is herein defined as “being of a designated size that can interoperatewith the other components described herein”. In addition, the definitionintended by use herein of the descriptive term “standard”, is thatdefinition meaning “something set up and established by authority, law,custom or consensus as the specific, uniform magnitude of a quantity,weight, extent, value, or quality”. It is reasonable that the nominal,nominal interoperable, or standard magnitudes of many of the parametersspecified herein could be changed in the future by some authority,consensus or enterprise with such change being across a conceivablerange of feasible magnitudes and with commensurate changes to otherinteroperable components of this transportation system while stillincluding such changed or alternative embodiments as legitimatelyencompassed by this patent. Consequently, a range of feasible andreasonable magnitudes are specified as the conceivable range followingseveral of the nominal, nominal interoperable, or standard magnitudesspecified in this specification/disclosure. In addition, a smaller ornarrower preferred range that is within that conceivable range may bespecified. The conceivable range and preferred range are not intended tobe limiting and will, where applicable, be specified in metric unitsalong with the nominal, nominal interoperable, or standard magnitudesthat are specified herein in metric units. The reasons for the selectionof these ranges will be given in light of the consequences of usingmagnitudes outside of these ranges. For most parameters, there is adeclared nominal interoperable magnitude as well as the specified rangesof feasible alternatives. In instances where the magnitude is presentedherein as either a specified standard or as a nominal interoperableembodiment, it is because such a specification is considered fundamentalto fulfilling the interoperability and performance requirements of thistransportation system.

The size of the cabin or people/payload compartment of the SkyQartaircraft to be used in the QUAD system has a direct effect on theaircraft's drag, power requirement and range; consequently thiscompartment must be of the minimum size that can still comfortablyaccommodate the most common sizes of people and payloads. Thepeople/payload compartment of the embodiment of the SkyQart describedherein is named the axisymmetric fuselage pod or AFP. The AFP has acircular cross section and a tapered shape that minimizes drag. Toenlarge the size of the AFP by scaling it up above its nominal 160.02 cmdiameter, even by a small amount, in an attempt to make it more spaciousand luxurious would impose a significant cost and speed penalty thatwould apply on every flight and thus be multiplied by the billions ofprojected trips flown. Likewise, to change its cross-sectional shapefrom circular to square would also impose a cost, speed andcompatibility penalty.

To limit its cost, the size of the land parcel needed for the SkyNestlikewise should be as small as practicable for safe operations withincommunity-acceptable noise limits. The nominal embodiments of theSkyNests presented herein all are of minimum parcel size. To minimizethis parcel size ultimately requires that the SkyQart aircraft beautonomous (pilotless). With precise autonomous control, said SkyQartmust fly consistently precise trajectories with curved traffic patternswith steep climb and descent profiles along with precise 4D approachesto precise landing touchdowns at each SkyNest. (The term 4D refers to anaircraft flight path whose approach and trajectory are specified bycombining its three-dimensional (3D) path with the exact time at eachlocation along that path, thus adding a 4^(th) dimension to 3D). Theautonomous flight control systems of the SkyQart aircraft provide itwith extreme reliability, aerial agility and negligible control latencyand enable it to fly precise 4D trajectories. Extreme reliability can bedefined as having a mechanical or software failure once in every onebillion flight operations.

Aerial agility of the SkyQart is important to this patent becauseminimizing community noise impacts of flight operations will, at someSkyNests, demand extremely short take-off and landing (ESTOL)performance with extremes of acceleration rate change that approach butdo not exceed levels that are tolerable to passengers of a publictransportation system. The SkyQart must have extreme capabilities forbrisk control of sink rate, climb rate, pitch, roll and yaw rates,thrust, lift and drag in order to operate at standardized small landingsites herein named SkyNests. Said SkyQarts must be highly agile and mustconsistently use an actuating principle that is particularly enabled inelectric-powered servo-controlled aircraft with negligible controllatency. That principle is herein named guided rate acceleration changeexecution (GRACE). The GRACE actuating principle involves the tailoringof the rate of actuation of movement across any range of motion ortrajectory so that it is acceptable in a public transportation system.This means that the changes in acceleration which are called the jerkrate, across any range of motion, must rise and fall at controlled ratesthat remain within known tolerable jerk rates for human occupants whilestill achieving the necessary precise motion in time.

The speeds required for the different autonomous robotic vehicles usedin the QUAD system are likewise constrained by operational and physicaldemands. The SkyQart's nominal interoperable lift-off and climb-outairspeed and landing airspeed is 24 m/sec, which is fast enough toensure that the aircraft's control surfaces will have enough dynamicpressure to maintain brisk control in gusty or turbulent conditions. Itis also fast enough to enable the cruise speed of the SkyQart aircraftto substantially out pace surface traffic even in high winds, whilebeing slow enough to enable short take-offs and landing rolls at verysmall SkyNests, as well as to provide enough time for the autonomouscontrol system to process and enact de-confliction with other airtraffic that is on sovereign autonomous trajectories. Alternativeembodiments of the SkyQart could use a landing speed that falls within aconceivable range that is 0 m/sec or more, 20 m/sec or more, 27 m/sec ormore, or any value between and including the speed values provided,while it is preferred that the take-off and climb-out airspeed be anominal interoperable 24 m/sec with a preferred range of 21.5 m/sec to27 m/sec. This landing speed The QUAD system will thereby enable notonly same day deliveries, but same hour deliveries for private users aswell as for major shippers like the US Postal Service, UPS, FedEx,Amazon and others. Designing a SkyQart for a substantially slowertake-off airspeed would reduce the expeditiousness of operations at theSkyNest and reduce its cruise speed, and this would not savesignificantly on land parcel size due to the concomitant need forcontainment of take-off noise within the SkyNest boundaries. The nominalinteroperable 7.6 m/sec speed for taxiing of the SkyQart is fast enoughto move with alacrity on the surface of the SkyNest while being slowenough to enable accurate autonomous trajectories, short stoppingdistances and tight turns. Alternative embodiments of the SkyQart mayhave a taxiing speed that is in a conceivable range of about 6 m/sec ormore, about 8 m/sec or more, about 9 m/sec or more, or any value betweenand including the speed values provided, while it is preferred that thetaxiing speed be 7.6 m/sec as this provides a preferred combination ofsafety, speed, maneuverability and expeditious traffic flow withoutexcessive noise, braking distances or delays. The nominal interoperable11 m/sec limit speed for the autonomous robotic delivery cart (RDC) onneighborhood streets is likewise fast enough to keep surface traveltimes short while slow enough to comply with safe speed limits for suchneighborhood electric vehicles. In its use confined to the dock premisesof a SkyNest, the autonomous robotic electric payload cart (EPC) has abattery pack sufficient to a maximum range of up to 4 km. The nominalmaximum speed of the EPC is constrained to the speed of a fast walk,just 2.2 m/sec, so that it can safely and autonomously move shortdistances along the dock premises that are congested with pedestrians.Alternative embodiments of the EPC may have a maximum speed that is in aconceivable range of about 2 m/sec or more, about 2.5 m/sec or more, orany value between and including the speed values provided, while it ispreferred that the EPC's maximum speed be 2.2 m/sec as this provides apreferred combination of safety, speed, maneuverability and expeditioustraffic flow without delays or danger to pedestrians.

Other constraints affect the sizing of the components for QUAD. Forexample, the autonomous robotic delivery cart (RDC) must be small enoughto qualify as a neighborhood electric vehicle¹ and fit in a bike laneyet large enough to carry two large people side-by-side or,alternatively, to carry a 122 cm wide cargo box or 122 cm×244 cm sheetsof plywood or other building materials. Its nominal interoperable lengthshould be less than 244 cm so that it can park perpendicular to the curband thereby consume only 25% of a parallel parking space.

The nominal interoperable size of the standard swappable battery packs(SBP) carried by the SkyQart must be large enough to provide sufficientrange for its market of short trips, while being small enough to bereadily interchangeable between SkyQarts. However, because the SkyQarthas no toilet, it is not necessary to provide it with the weight burdenon every flight of a battery sufficient for a 2-hour flight. The batterypacks must also be limited in size and weight such that they can behandled manually by a pair of strong adults and can be stackable anduseable in parallel circuits for applications that demand extended rangeor power. The packs must also have provisions for tire and smokecontainment, ventilation and cooling and a built-in battery managementsystem, along with consensus standards for size and location ofelectrodes and latch points. The dimensions of the standard swappablebattery pack (SBP) for the SkyQarts are chosen specifically to fitpresent day energy densities and the commonly available volumes intwo-seat vehicles and should become a consistent industry standard muchlike the familiar ‘D cell’ flashlight battery. A 600-volt standard isanticipated for this SkyQart battery pack. Alternative embodiments ofthe SBP may have a pack voltage within a conceivable range of about 400volts or more, about 700 volts or more or about 800 volts or more, orany value between and including the voltage values provided, while it ispreferred that the nominal interoperable voltage be 600 volts with apreferred range of 550 to 650 volts as this provides a preferredcombination of safety, weight savings and industry compatibility withoutexcessive risk of shock, insulation breakdown, or internal shorting ofhigher voltages. The energy density of the SBP will increase in thefuture as new, more advanced battery chemistries evolve and this willallow its weight to be reduced while still fitting, latching andconnecting inside the standard embodiment of the battery receptacle in aSkyQart.

The autonomous robotic electric payload cart (EPC) is an innovation toreduce boarding time and thereby turnaround time. The EPC has a nominalinteroperable ground clearance of 2.54 cm in order to maximize theheadroom for passengers seated on an EPC inside the SkyQart. Alternativeembodiments of the EPC may have a ground clearance within a conceivablerange of about 3 cm or more, about 5.1 cm or more, or any value betweenand including the ground clearance values provided, while it ispreferred that the nominal interoperable ground clearance be 2.54 cm asthis provides a preferred combination of passenger headroom, weightsavings, latching security, ride height atop the RDC and cost savings.This 2.54 cm ground clearance means that off-loading an EPC onto theground level from the lowest deck height of an autonomous roboticdelivery cart (RDC), which is nominally 35.56 cm above the pavement,requires a specially shaped ramp whose slopes are gradual enough to notcause the undersurface of the EPC to scrape on the ramp duringoff-loading. The ramp's curved shape is customized such that it will fitEPC's small ground clearance at all positions along the ramp even with a60 cm overhang at the front and rear of the EPC.

Aircraft noise emissions at all boundaries of a QUAD SkyNest are to be≤55 dBA LA_(eq), 5 s at a 40 m sideline, which would make it inaudiblein the presence of ambient noise of 67 dBA. Moreover, such SkyQart noiseemissions should be as low as possible, with ≤40 dBA at 40 m as an idealnoise level. Alternative embodiments of the SkyQart aircraft may have anoise emission at a 40 m sideline distance during full power take-offwithin a conceivable range of about 40 dBA LA_(eq), 5 s or more, about44 dBA LA_(eq), 5 s or more, about 46 dBA LA_(eq), 5 s or more, about 50dBA LA_(eq), 5 s or more, about 58 dBA LA_(eq), 5 s or more or any valuebetween and including the noise levels provided, while it is preferredthat the nominal interoperable full-power take-off noise emissions be≤55 dBA LA_(eq), 5 s with a preferred range of 50-57 dBA LAeq, 5 sbecause this provides a preferred combination of communityacceptability, achievable quietness, reduced size of the SkyNest,sufficient propeller tip speeds, low cabin noise and improved ridership.These noise requirements and the operational requirements for a veryshort runway combine to dictate the size of the standard SkyNest landparcels as being the smallest parcels that can safely fulfill both ofthese conflicted requirements.

The solenoid-actuated pin latching system depends upon use ofsolenoid-actuated latching pins made of high-strength, hardened steel.These pins each have a bullet-nose shape and are of a nominalinteroperable 6.35 mm diameter. Alternative embodiments of thepin-latching system may have a latching pin diameter within aconceivable range of about 5 mm or more, about 7 mm or more, about 10 mmor more or any value between and including the diameter values provided,while it is preferred that the nominal interoperable pin diameter be6.35 mm with a preferred range of 5.5-7 mm because this provides asufficient strength, light weight, industry sizing compatibility, andmass sufficient for strong actuating forces. Since the QUAD standardembodiment calls for there to be a nominal gap of only 3.81 mm betweenthe solenoid body block and the edge of the EPC surface deck at thelocation of the hole into which the pin inserts, these pins are loadedmainly in shear. Alternative embodiments of the pin-latching system mayhave a gap within a conceivable range of about 3.5 mm or more, about 5mm or more, about 7 mm or more, or any value between and including thegap values provided, while it is preferred that the nominalinteroperable gap value be 3.81 mm with a preferred range of 3.5-5 mmbecause this provides the minimum gap that offers sufficient clearancefor rapid loading, light weight, avoidance of bending loads, and shearstrength sufficient for the expected loads. The pin's shear strength of896,324 kPa can enable each pin to withstand a shear load of over 26689Nand thus provide highly weight-efficient fixation of movable loads.

This invention uses a comprehensive approach to fulfill the severalrequirements of on-demand mass transportation with a combination ofspecific technologic, operational and process innovations that,together, comprise a new, sustainable, environmentally friendly system.The several components of the QUAD system comprise a new and uniquecombination distinct from other models of urban air mobility bycombining efficient, ultra-quiet, autonomous or optionally piloted ESTOLaircraft that haul either passengers or cargo or both with interoperablecarts capable of rapid, automatic solenoid-actuated latching withpre-boarding of passengers and pre-loading of cargo. In its entirety,community acceptability, specificity, precision, interoperability,standards, affordability, environmental friendliness and mass capacity,this invention differs substantially and in numerous ways from all priorvisions, models and proposals for urban on-demand aviation services.

QUAD can fulfill the need for an efficient, electric-powered publictransportation system in which the entire trip from doorstep to doorstepis made as quickly and as safely as possible with a minimum ofinconvenience or discomfort. The modal changes from walking to surfacevehicle to air vehicle and back again must be facilitated by theadoption of four basic components of the QUAD transportation system: 1)its highly distributed network of accessible, small standardizedairparks (SkyNests); 2) its autonomous robotic surface cart vehicles,the EPC and RDC; 3) its versatile ultra-quiet, V/ESTOL SkyQarts; and 4)the corollary standards and nominal magnitudes for its interoperablecomponents. QUAD must provide these four components in a way that canfulfill the needs of everyone, including the disabled, injured,incapacitated, elderly and small children. QUAD must also provide thesein a way that can fulfill the most common needs of commercial, publicand private hauling of cargo, delivery parcels, building materials,equipment, tools and supplies.

Uncertain travel times happen mainly due to surface congestion, which istypically prevalent on freeways in urban and suburban areas. Uncertaintytime is typically minimized on residential streets. The QUAD systemminimizes uncertainty time by avoiding travel on freeways and by insteadusing small neighborhood electric vehicles called robotic delivery carts(RDC) that can use residential streets and bicycle lanes for what in theUSA is called “last mile” connectivity, i.e. neighborhood delivery,thereby largely avoiding freeway and other congestion delays.

SkyNests must offer consistent standards in size, equipment andfacilities in order to fit the cart vehicles defined herein and toefficiently achieve high capacities and safe operations. These standardsare as important as those for the gauge of railroad tracks. For the sakeof reducing costs and speeding implementation, these standards areintended to be international and are conceived to respect internationalcultural, dimensional and regulatory requirements. This inventionincludes the specifications and operational descriptions of thesestandards. SkyNests for QUAD must be small enough that they can be sitedvery near to where people live and work. Such high proximity siting alsocalls for operations at these SkyNests and the SkyQarts that fly thereto fulfill three important but conflicted requirements, which are: 1)safe, high capacity and high proximity operations and 2)community-acceptable levels of aircraft noise and 3) precise, 4D steepapproach and climb-out gradients. The simultaneous fulfillment of thesethree requirements distinguishes QUAD from all other prior art.

SkyNests must be sited with high proximity to where people live and workin highly distributed networks across urban/suburban areas as sharedcommunity assets. Such high-proximity siting means the SkyNest site canbe reached in a minimum of ground travel time. This brief ground traveltime is important to offering QUAD travelers the benefit of saving morethan 30 minutes on flights as short as 16 km, a benefit that helps QUADreach a meaningful mass-market size that can deliver its many societalbenefits. In the example case, users can travel up to 4 km onnon-gridlocked residential streets at an average of 40.2 km to reach aSkyNest in less than 6 minutes (i.e., 1/10^(th) of an hour). The vehicleused for that surface travel could be any of a number of specializedground vehicles, including a bicycle, scooter, Low-Speed Vehicle (LSV),Neighborhood Electric Vehicle (NEV), modified golf cart as well as aRobotic Delivery Cart (RDC) as described herein. If communities allocatea nominal 1.28 ha land parcel for a SkyNest I to be sited at the centerof every circle of 8 km diameter, each SkyNest I requires only 0.63% ofthe land area of the neighborhood that it serves. As a general guidelineto the ideal ubiquity of SkyNests, a city should have about one SkyNestfor every two of its high schools. From any SkyNest, commuters couldsave time and parking or bridge fees by riding a SkyQart to any of thewidely distributed SkyNests in the QUAD system. SkyQart operations mustbe safe and quiet enough to cause minimal fear and noise annoyance tothe neighbors living nearby the SkyNest. Vertical take-off and landing(VTOL), tilt-wing, tilt-rotor or multi-rotor (copter) aircraft areinherently noisier than fixed wing aircraft and so would require largerSkyNests in order to be community acceptable. The siting of these largerSkyNests would usually entail less proximity to where people live and sowould adversely increase the ground travel time that is important toeconomic feasibility. In addition, VTOL tilt-wing, tilt-rotor ormulti-rotor (copter) aircraft typically require more time for hoveringapproaches and departures that reduce operational capacity. Therefore,although VTOL, tilt-wing, tilt-rotor or multi-rotor (copter) designs asalternative embodiments could theoretically be used in the QUAD systemif they offered compatible dock loading, the nominal interoperable andpreferred embodiment of the SkyQart presented herein is that of afixed-wing aircraft.

The multiple system and vehicle requirements of QUAD are irrevocablyinter-dependent, and they constrain the actual design requirements ofits SkyQart aircraft, its SkyNests and its operational components. Thearea needed for a SkyNest is within a conceivable range of between 0.4and 5.0 ha, with a nominal area of 1.28 ha and a preferred range of1.2-2.4 ha. SkyNest facilities must include compatible docking andprocessing equipment for both vehicles and passengers. There is a‘just-right’ set of performance and capability requirements for theSkyQart aircraft that can provide high capacity operations and precise,4D, steep flight paths at such SkyNests. These necessary aircraftperformance capabilities can only be achieved by the combination ofseveral innovations and technologies into the new category of aircraftnamed herein as the SkyQart. The fixed-wing SkyQart aircraft presentedherein represent the nominal interoperable embodiments but not the onlyembodiments of the flight vehicles that can serve in the QUAD system.

The mission requirements of the aircraft necessary to QUAD are of aknowable range and they comprise an integral part of this invention.These mission requirements dictate that the SkyQart be a new and uniquecategory of aircraft, the nominal interoperable embodiment of which willhave the features, innovations and performance capabilities describedherein.

The invention(s) in this patent are distinguished as unique because theydefine the detailed, specific, and concerted processes, ultra-quietelectric-powered vehicles, components, landing facilities and standardsnecessary for a sustainable, highly distributed, interoperable,comprehensive on-demand system of mass transportation and cargo deliveryby air for urban mega-regions and beyond. In order to be sustainable atthe scale necessary for mass transportation, with its automated,high-capacity operations at SkyNests, QUAD requires this strictlydefined, comprehensive set of integrated standards, specifications,performance capabilities and concepts of operations for its SkyNests andits air and ground vehicles. The QUAD SkyQarts are integrated andnetworked with other specialized electric-powered surface vehicles,facilities and accessories that enable high-capacity operations atSkyNests. This invention is a public transportation system that includesthe vehicles, facilities, accessories and operations as its importantcomponents. This invention employs electric aircraft technologies andtheir practical application to sustainable transportation solutions thatcan meaningfully benefit society and enhance productivity while reducingsurface gridlock, infrastructure costs and greenhouse gas emissions.

The importance of interoperability of components in the QUAD systemmeans that they are to be taken as an integrated system of componentsthat are interdependent. The many components of the QUAD system enableone another so as to enhance the overall system efficiency, capacity andaffordability. Their interdependency means that changing the magnitudeof any one parameter of a component specified herein as the nominalinteroperable magnitude, in terms of its size, weight or performance,will for the sake of interoperability, require the changing of relatedparameters on a number of other components of the QUAD system. Inaddition, this interdependency of the components of the QUAD system andtheir relative uselessness as stand-alone components affirms the needfor these several components to be patented as a transportation systemrather than as separate patents. Changes from the standards and nominalinteroperable magnitudes presented in the embodiments herein thatnevertheless remain within the conceivable ranges cited herein aretherefore part of this invention. For all of the variants of SkyQartsand autonomous robotic electric vehicles described herein, the presentinvention is susceptible of embodiment in different forms. There isshown in the drawings and herein described in detail one or morespecific embodiments, with the understanding that the present drawings,disclosure and claims are exemplary of the principles and concepts ofoperation of the system as an invention as comprising an article that isa complete, integrated and interoperable transportation system. Thesespecific embodiments are not intended to limit the invention to onlythose specific embodiments that are shown and described. Moreover, whilethe representative embodiments herein have been described in specificdetail with certain components in exemplary configurations that candemonstrate and serve as interoperable standards, it will be understoodby one of ordinary skill in the art that other conceivable combinationsof embodiments can be implemented using similar but differentspecifications, configurations and/or different components. For example,it will be understood by one of ordinary skill in the art that the size,shape, speed, operation or number of certain components can be alteredwithout substantially impairing or changing the concept or functioningof this invention's interoperable transportation system, provided thatsuch alterations are made interoperable. The representative embodimentsand disclosed subject matter, which have been described in detailherein, are presented by way of example and illustration and not by wayof limitation or exclusion of other variants, it will be understood bythose skilled in the art that various changes may be made in the formand details of the described embodiments resulting in equivalentembodiments that remain within the scope of the appended claims.

The SkyNest Dock Standards include a 47 cm dock height. The dock heightrequires the adoption of a standard because it is deterministic ofseveral other dimensional magnitudes in the QUAD transportation system.Alternative embodiments of the dock standards may have a dock heightwithin a conceivable range of about 41 cm or more, about 44 cm or more,about 50 cm or more, about 61 cm or more or any value between andincluding the dock height values provided, while it is preferred thatthe nominal interoperable dock height be 47 cm with a preferred range of45-50 cm because this provides a height low enough to fit a SkyQart'slow-set cabin floor height (which is essential to its short take-offcapability without wheelies) and to allow an adult human to climb uponto the dock as needed, while still being high enough to provide roomunderneath the dock for battery swapping equipment, service bays andparked main landing gear tires. The under-dock service bay is largeenough to contain robotic battery swapping using SBP drawer slides andbattery charging racks. The nominal interoperable dock width is 7.47 m.Alternative embodiments of the dock width may have a width within aconceivable range of about 6 m or more, about 9 m or more, about 12 mmor more or any value between and including the width values provided,while it is preferred that the nominal interoperable dock width be 7.47m with a preferred range of 7-8 m as this provides sufficient room forbi-directional passenger walkways that preserve social distancing, alongwith adequate width for under-dock service bays and for EPC carts tosafely maneuver on the dock surface, with a dock width that is stillsmall enough to limit land parcel size and expedite passengerthroughput.

The battery charging rack under the dock for robotic battery swapping.

The robotic battery swapping underneath the dock using a specializedrobot arm that can swap an SBP in a SkyQart in under 1 minute andnominally in only 10 seconds.

The Axisymmetric Fuselage Pod (AFP)

The axisymmetric fuselage pod (AFP) is an important component to thisinvention because its shape enables two key capabilities of the SkyQartaircraft used in the QUAD system; longer flight range and rapid loadingand unloading of payloads. The AFP is a streamlined shape with a nominalinteroperable 160.02 cm (range is from 125 to 180 cm) maximum outsidediameter. Alternative embodiments of the AFP may have a maximum outsidediameter within a conceivable range of about 125 cm or more, about 150cm or more, about 180 cm or more or any value between and including thediameter values provided, while it is preferred that the AFP diameter bethe nominal interoperable size of 160.02 cm with a preferred range of150-165 cm because this provides sufficient room for passengers, commoncargo, battery pack and active landing gear while being small enough tominimize wetted area drag, weight, and cost. The AFP shape has a nominal2.93 to 1 fineness ratio of length to width, giving the embodiment aspresented herein a total length, L_(d), of 4.69 m. It is a body shapewhose computational fluid dynamics predict a very low form drag and itserves as the fuselage and cabin of the SkyQart. To minimize drag andmaximize range for the SkyQart, the size of the AFP is chosen as thesmallest that can adequately and comfortably enclose the most commontypes of payloads that need to be carried in QUAD. Those most commontypes of QUAD payloads are expected to be two adult people seatedside-by-side or a cargo whose maximum horizontal dimensions are 121.92cm by 243.84 cm. The rear portion of the AFP forms a hatch that iseffectively a door that opens on a sturdy hinge and swings 90° to theside and upward at an 18° angle. With the nominal interoperable 2.54 cmwall thickness of the AFP, the open hatch provides a large, 151.7 cmopening that allows rapid loading and unloading at the dock of EPCsladen with various types of payloads. Alternative embodiments of the AFPmay have a wall thickness within a conceivable range of about 1.27 cm ormore, about 2 cm or more, about 3.81 cm or more or any value between andincluding the thickness values provided, while it is preferred that thewall thickness be the nominal interoperable 2.54 cm with a preferredrange of 2-3.5 cm because this provides a preferred combination ofstrength, low weight, industry sizing compatibility, hatch opening sizeand internal space. The AFP's hatch opening also exposes a DCfast-charger interface plug that can be used for recharging theSkyQart's standard swappable battery pack (SBP). The rear portion of theAFP fuselage aft of the hatch also serves as a floatation device. Itsinternal volume, like that of other empty volume spaces in the SkyQart,is sealed and filled with buoyant rigid closed-cell foam. The sealedfoam in the rear hatch is divided into three compartments, two of whichare removable modules that, when removed, can provide additional spacefor passenger seats to recline or for outsized baggage and cargo.Flotation module #1 is nominally 55.9 cm L×114.3 cm H×122 cm W. It isnominally 122 cm wide at the fuselage waterline of the seat armrests,narrowing to 101.6 cm wide at the shoulder waterline. These dimensionswould change for alternative embodiments within the size ranges givenfor the AFP. The bottom of module #1 is at the waterline of the cabinfloor of the SkyQart. Module #1 fits into the rear hatch in a recess inthe upper front surface of flotation module #2. The absence of thismodule #1 offers an empty volume of space in which the rear baggage binand the upper rear portion of the rear seats of a two-seat EPC canrecline rearward up to 30°, regardless of which of the four latching pinreceptacles are used by the EPC. This empty volume of space is alsolarge enough to contain the larger cargo that occurs when the Main CargoBox includes both its forward and aft cargo extension boxes. This emptyvolume of space from module #1 is also useful to contain payload in thecase of a three-seat EPC, though the space available for reclining therear seats and smaller rear baggage bin are in that case more limited.The other removable flotation module, module #2, is much larger and isremoved when carrying an EPC loaded with out-sized, extra-long cargosuch as building materials. It has a carve-out on its forward face thatexactly fits the shape of module #1 and provides a small strap fastenerfor joining module #1 to module #2. Excepting the volume of module #1,the volume of module #2 completely fills the interior volume thatextends 96.52 cm aftward into the rear hatch from the hatch opening. Allother internal volume space of the rear hatch, excluding that of Module#1 and Module #2, is likewise sealed and filled with buoyant rigidclosed-cell foam.

The rear hatch of the pod can be displaced aftward by the insertion of anominal 60.96 cm length of cylindrical fuselage extension to create alarger AFP with enough space to carry standard building materials. Thesebuilding materials, when properly loaded, can be as large as 122 cm×244cm sheets of plywood or 365.8 cm lengths of “two by twelve” lumber³ thatis 3.8 cm high×28.6 cm wide. These and other building materials can bestacked atop a special cargo hauling attachment that is a latching rackthat pin-latches to the EPC's seat latching tracks. Alternatively,several other cargo hauling attachments for other types of cargo canpin-latch to the EPC's seat latching tracks. The surface of the specialrack is a nominal 30.5 cm above the EPC's deck surface so that, when thebuilding materials are securely strapped to this rack, they will be inan axial position inside the cargo AFP that offers a space of maximumlength for the 365.8 cm long lumber.

The axisymmetric fuselage pod's scalable surface coordinates, relativeto the total length, L_(t) of its central axis, are given in the Table1, below, and are designated as the fractions X/L_(t) and Y/L_(t). Theparameter X/Lt is the longitudinal coordinate given as a fraction of thetotal length, L_(t). The parameter Y/L_(t) is the vertical or thicknesscoordinate given as a fraction of the total length, L_(t). It will benoted that the diameter of the AFP, at any point X/L_(t) along itscentral axis where Y/L_(t) is known, is therefore equal to(2×Y/L_(t))×L_(t). An example of this calculation of the diameter of thepresent standard embodiment, taken from Table 1, below, is that whereX/L_(t)=0.471 and Y/L_(t)=0.169 and L_(t)=4.69 m, the diameter at thatlongitudinal station of the AFP will be (2×0.169)×4.69 m=1.585 m.

TABLE 1 Axisymmetric Fuselage Pod Surface Coordinates X/L_(t) Y/L_(t)X/L_(t) Y/L_(t) 0.000 0.000 0.471 0.169 0.000 0.002 0.483 0.170 0.0010.006 0.494 0.170 0.001 0.010 0.506 0.171 0.003 0.014 0.517 0.171 0.0060.020 0.529 0.170 0.010 0.025 0.540 0.170 0.014 0.031 0.552 0.170 0.0170.034 0.563 0.169 0.023 0.039 0.575 0.169 0.029 0.044 0.586 0.168 0.0340.048 0.598 0.167 0.040 0.052 0.609 0.166 0.046 0.055 0.621 0.164 0.0570.062 0.632 0.162 0.069 0.068 0.644 0.160 0.080 0.073 0.655 0.158 0.0920.078 0.667 0.155 0.103 0.083 0.678 0.151 0.115 0.087 0.690 0.147 0.1260.091 0.701 0.143 0.138 0.096 0.713 0.138 0.149 0.099 0.724 0.133 0.1610.103 0.736 0.127 0.172 0.107 0.747 0.121 0.184 0.111 0.759 0.115 0.1950.114 0.770 0.108 0.207 0.118 0.782 0.101 0.218 0.121 0.793 0.093 0.2300.124 0.805 0.086 0.241 0.128 0.816 0.078 0.253 0.131 0.828 0.071 0.2640.134 0.839 0.064 0.276 0.137 0.851 0.057 0.287 0.140 0.862 0.051 0.2990.143 0.874 0.045 0.310 0.145 0.885 0.040 0.322 0.148 0.897 0.035 0.3330.150 0.908 0.030 0.345 0.153 0.920 0.025 0.356 0.155 0.931 0.021 0.3680.157 0.943 0.017 0.379 0.159 0.954 0.014 0.391 0.160 0.966 0.010 0.4020.162 0.977 0.007 0.414 0.164 0.983 0.006 0.425 0.165 0.989 0.005 0.4370.166 0.994 0.005 0.448 0.167 0.997 0.005 0.460 0.168 1.000 0.005

The smoothly curved continuity of the AFP's stressed composite skin isinterrupted only for the openings for the rear hatch, the nosewheellanding gear well, the two main landing gear trunnion pillow blockbearings, the rooftop monostrut attachment opening, the two windscreensand the two large circular side windows, which also serve as emergencyexits. All openings are kept as small as possible to maintain thestrength and smoothness of the AFP. The edges and gaps of all openingsare faired to smoothly continue the AFP's external shape and their gapsare made as narrow as possible. Embedded into the nominal 2.54 cm thickcomposite sandwich that comprises the skin of the AFP are severalreinforced carbon fiber ribs, bulkheads, spines, stringers, ribs andlongerons, most of these with a cross-sectional shape that is ahat-section. The midline longitudinal roof spine that separates the twowindshields is a nominal 8.9 cm in width, and it has a materialthickness that bears major structural loads imposed by the nosegear andAFP rooftop monostrut main wing attachments. The AFP also has amid-fuselage circular circumferential structural bulkhead that isembedded into the skin of the AFP and that reinforces its floorboardsand its other spines, stringers, longerons and bulkheads, while alsospreading the loads from the forward wing attachment onto the roof ofthe AFP. There is a diagonal embedded bulkhead that joins the lowerportion of the mid-fuselage bulkhead to the more aftward circular hatchdoor bulkhead and spreads the loads from the main wing attachment on theroof of the AFP to the AFP's lower and forward structures. There is along horizontal longeron that joins the rear bulkhead to the middle,diagonal and forward bulkheads and stiffens the side of the AFP. Thecircular rear bulkhead of the AFP stiffens its rear hatch opening anddissipates loads from both the wing and the main landing gear. Thereinforced monostrut attachment points and other hard-points are moldedinto the composite structure of the AFP at the time of its manufacturingand cure, and they each have several smaller reinforced micro-ribsradiating outward from them in order to more widely spread theattachment loads organically onto the walls of the AFP. Some of theribs, roof spine, bulkheads and longerons are structural items that mayhave wiring harnesses embedded inside them with outer shielding of thoseharnesses that dissipates and diffuses lightning and radio frequencyinterference (RFI) energy away from critical structures and components.In some embodiments, some of these structural items in the walls of theAFP may also contain flight control cables. The port and starboard sideof the AFP each have a circular cabin side window of a nominalinteroperable 71.12 cm diameter that serves as an emergency escape exitin accordance with FAR 23.807. Alternative embodiments of the emergencyescape exit windows may have a diameter within a conceivable range ofabout 61 cm or more, about 81 cm or more, about 91.5 cm or more or anyvalue between and including the diameter values provided, while it ispreferred that the window diameter be the nominal interoperable 71.12 cmbecause this provides a preferred combination of sufficient size, lowerweight, FAA compliance, outward field of view and minimized disruptionof the AFP's stiffness and surface smoothness. Each emergency exitwindow has a window frame that is a structurally reinforced ring thatitself serves as a bulkhead that adds to the strength and shapeintegrity of the AFP. The window frame on the AFP has a smoothly roundedcross-section so that it can safely serve as an emergency exit. Thecircular windows themselves are made of clear acrylic or polycarbonateand are of a nominal thickness of 4.76 mm. Each window has an internalperimeter flange that closely fits the window frame and that ensuresthat the window cannot be pushed or sucked out of the AFP at any time.The perimeter flange is indexed with dowel pins to ensure that thewindow is always correctly installed on the window frame. There are anumber of finger-grip holes in the internal surface of the window'sperimeter flange to facilitate gripping and pulling the window inwardtoward the SkyQart's cabin in the event that it is to be used as anemergency exit. Before doing so, the thin peelable sealing tape thatseals the perimeter flange of the window to the inner wall of the AFPneeds to be manually stripped away, and this can be readily performed bya person of ordinary strength and dexterity. Peeling this tape isfacilitated by the provision of small grip rolls at the ends of thetape. Both the window perimeter flange and the window frame are equippedwith specially located narrow grooves that run entirely around thecircle of the window and that engage the flexible nipples on theextruded external rubber seal that is pressed into the external gapbetween the window and the window frame. This rubber seal may be pressedor lightly glued in place such that its edges form a flush interfacewith the external contour of the AFP. Both this rubber seal and theinternal sealing tape on the window flange serve to secure the window tothe aircraft and prevent air leaks around its perimeter. Both the rubberseal and the sealing tape are replaceable are both are designed to alloweasy removal of the window in case of an emergency. In extremeemergencies, the circular window can be removed by forcibly pushing orkicking it inward toward the cabin from the outside of the aircraft.

The SkyQart I and SkyQart II

The SkyQart I and II are important components to this invention. Theyare specialized, standardized small fixed-wing aircraft expresslydesigned for the QUAD system to provide efficient hauling of the mostcommon types of payload across distances of from as little as 16 km tomore than 220 km. Its size, docking connections, power, speed, and shortrunway capabilities are chosen as workable standards to fit theprocesses and dimensions of the QUAD transportation system. Its coremission requirements are nominally:

a SkyQart that takes off within 43.9 m (144 feet) of its point of brakerelease at sea level in zero wind. Alternative embodiments of theSkyQarts may have a take-off distance within a conceivable range ofabout 0 m or more, about 35 m or more, about 52 m or more, about 68 m orany value between and including the said distances provided, while it ispreferred that the take-off distance be the nominal interoperable 43.9 mwith a preferred range of 40-50 m because this provides a combination oftolerable G forces, low noise emissions, safe lift-off speeds andSkyNests that comprise small land parcels.

a SkyQart that has a cruise flight airspeed of at least 193 km/hr at analtitude that is less than or equal to 914.4 m (3000′) above mean sealevel. Alternative embodiments of the SkyQarts may have a cruise speedwithin a conceivable range of about 140 km/hr or more, about 210 km/hror more, about 240 km/hr or more, or any value between and including thecruise speeds provided, while it is preferred that the cruise speed bethe nominal interoperable 193 km/hr with a preferred range of 180-225km/hr as this provides a preferred combination of short runwaycapabilities, reduced land parcel size, improved energy efficiency,enhanced range, manageable power requirements and air trafficcoordination.

a SkyQart that has a flight range of at least 193 km with 10-minutereserve. Alternative embodiments of the SkyQarts may have a flight rangewithin a conceivable range of about 100 km or more, about 170 km ormore, about 240 km or more, or any value between and including themaximum range values provided, while it is preferred that the nominalinteroperable maximum range be ≥193 km with a preferred range of 140-200km because this provides a workable compromise in terms of safety,minimizing battery swaps, minimizing battery pack weight, extendingridership possibilities, improving ride quality and reducing aircraftdocking station size requirements.

a SkyQart whose maximum rate of climb at gross weight is at least 9.14m/sec at an indicated airspeed of 24 m/sec at sea level. Alternativeembodiments of the SkyQarts may have a maximum rate of climb within aconceivable range of about 6 m/sec or more, about 8 m/sec or more, about10 m/sec or more, about 12 m/sec or more or any rate between andincluding the maximum rates provided, while it is preferred that themaximum rate of climb be ≥9.14 m/sec with a preferred range of 8-10m/sec because this, along with curved traffic patterns, provides asufficiently rapid gain of height to keep the acceptable noise sphereinside the boundaries of the SkyNest without demanding excessive amountsof installed power, excessive noise or unwieldly long wingspans, andthis helps to keep the SkyNest land parcels small enough to enable themto be sited with high proximity to where people and goods needs to go.

a SkyQart whose maximum take-off noise emission is ≤55 dBA LAeq, 5 s asmeasured at 1 m height above ground level at a 40 m distance along anyradius extending outward from the midline of the aircraft's nose.Alternative embodiments of the SkyQarts may have a maximum take-offnoise emission within a conceivable range of about 42 dBA LAeq, 5 s orless, about 48 dBA LAeq, 5 s or less, about 57 dBA LAeq, 5 s or less orany value between and including the maximum levels provided, while it ispreferred that the maximum level be the nominal interoperable level of≤55 dBA LAeq, 5 s with a preferred range of 50-57 dBA because thisoffers the best compromise in the power, thrust, propeller diameter andRPM needed while minimizing the size of the SkyNest land parcelnecessary to contain the acceptable noise sphere.

a SkyQart that can carry an EPC that has one or two seats or Qusheats,each of which has a capacity of 120 kg or more.

a SkyQart that can carry an EPC that has three seats or Qusheats, eachof which has a capacity of 91 kg or more.

The nominal embodiments of the SkyQart I and II presented herein eachare 6.7 m long and have a nominal interoperable wingspan of 10.97 m.Alternative embodiments of the SkyQarts may have a wingspan within aconceivable range of about 8 m or more, about 10 m or more, about 12 mor more, about 14 m or more or any value between and including thewingspans provided, while it is preferred that the wingspan be thenominal interoperable 10.97 m with a preferred range of 10-12 m becausethis provides a manageable wing weight and ride quality, an efficientaspect ratio and maximum glide ratio, a sufficiently rapid gain ofheight to keep the acceptable noise sphere inside the boundaries of theSkyNest without demanding excessive amounts of installed power,excessive noise or unwieldly long wingspans, and this helps to keep theSkyNest land parcels small enough to enable them to be sited with highproximity to where people and goods needs to go.

The SkyQart I and II each have a nominal interoperable wing area of11.44 sq m. Alternative embodiments of the SkyQarts may have a wing areawithin a conceivable range of about 10 sq m or more, about 12 sq m ormore, about 14 sq m or more, about 16 sq m or more or any value betweenand including the wing areas provided, while it is preferred that thewing area be the nominal interoperable 11.44 sq m with a preferred rangeof 11-13 sq m because this, along with the high lift coefficient of theSkyQart's fast flap system, provides a low enough stall speed withoutdemanding excessive amounts of wetted area drag, installed power orexcessive noise, and this enables the ESTOL performance that helps tokeep the SkyNest land parcels small enough to enable them to be sitedwith high proximity to where people and goods needs to go.

The SkyQart I and II each have a nominal interoperable maximum grossweight of 857 kg. Alternative embodiments of the SkyQarts may have amaximum gross weight within a conceivable range of about 800 kg or more,about 900 kg or more, about 1050 kg or more, about 1220 kg or more orany weight between and including the maximum gross weights provided,while it is preferred that the maximum gross weight be the nominalinteroperable 857 kg with a preferred range of 840-900 kg because thisprovides a sufficiently rapid gain of height during climb-out to keepthe acceptable noise sphere inside the boundaries of the SkyNest withoutdemanding excessive amounts of installed power, excessive noise orunwieldly long wingspans, and this helps to keep the SkyNest landparcels small enough to enable them to be sited with high proximity towhere people and goods needs to go.

a SkyQart that has a 20° forward sweep in the trailing edge of itsvertical tail.

a SkyQart that has a main wing aspect ratio of 10.525:1. Alternativeembodiments of the SkyQarts may have a wing aspect ratio within aconceivable range of about 8 or more, about 12 or more, about 14 or moreor any aspect ratio between and including the aspect ratios provided,while the nominal interoperable aspect ratio of 10.525:1 is preferredwith a preferred range of 10:1 to 12:1 because it provides an energyefficient airframe with reduced induced drag and a manageable wingweight, and reduces the demand for climb power and thereby avertsexcessive noise.

a SkyQart that has a main wing that has double-slotted flaps of largespan.

a SkyQart that has a trailing edge of the main wing that is sweptforward by a nominal 8.2° with a nominal 142.3 cm wing chord at thefuselage midline.

a SkyQart that has a nominal wing chord that tapers to 140.3 cm at theflap root, where the nested flap segments occupy a nominal chord lengthof 45.8 cm.

a SkyQart that has a total flap span that is a nominal 71.82% of thetotal wingspan.

a SkyQart that has its mid-point of the range of acceptable e.g.slocated nominally at the fuselage station (FS) 200.6 cm.

Alternative embodiments of the SkyQart I and II may have measurementsthat are different from these nominal ones given herein, and thosedifferences may or may not be made compatible and interoperable with theother components of the QUAD transportation system, though componentcompatibility and interoperability are very important to sustaining sucha transportation system.

a SkyQart that has a nominal aileron chord that is 28.%% of the wingchord at the inboard aileron edge.

a SkyQart that has a wing mean aerodynamic chord (m.a.c.) that isnominally 118.5 cm.

a SkyQart that has flaps that, when fully deployed and blown by thepropellers, can produce a maximum lift coefficient of ≥4.8. The flapshave their high lift coefficient substantially augmented or reduced ondemand by modulating the airflow over the flaps by varying the thrust ordrag of the large propellers.

The nominal interoperable height of the AFP belly skin above groundlevel is 21.6 cm. Alternative embodiments of the SkyQarts may have abelly height above ground level with a conceivable range of about 17 cmor more, about 23 cm or more, about 30 cm or more or any height betweenand including the belly heights provided, while it is preferred that thebelly height be the nominal interoperable 21.6 cm with a preferred rangeof 18-24 cm because this provides a low center of gravity to avoidwheelies on take-off while providing sufficient height to allow a longtravel of the landing gear, a workable dock height and enough space forthe standard swappable battery pack (SBP) to be carried below theSkyQart's cabin floor. The standard cabin floor height is 47 cm aboveground level, which matches the preferred standard dock height of theupper surface of the SkyNest docks. These standard dimensions for bellyheight, cabin floor height and dock height are deterministic for othercomponents including the tire and wheelpant height, dock height, seatheight, cabin headroom, elbowroom, rear hatch swing clearance, mainlanding gear trunnion pillow block bearing track width, EPC track width,resistance to wheelies, and other component parameters. This means thatif the AFP cabin floor height is changed in alternative embodiments ofthe SkyQarts, then the dimensions of all of these other interoperablecomponents will be compelled to also change. These interdependencies ofthese components clarify and emphasize the need for the nominalinteroperable QUAD transportation system to provide herein a set of‘just-right’ standards that are internally consistent, mutuallycompatible, and scaled to about the 95^(th) percentile of human needs.

To make room for the size of a standardized battery pack (SBP) withsufficient energy for the SkyQart's performance envelope, the topsurface of the cabin floor of the SkyQart is nominally located 25.4 cmabove the lowest point on the belly skin of the AFP.

The wing chord at the SkyQart I and II ailerons outer edge is nominally52.5 cm. The aileron chord at its outer edge is nominally 14 cm, whichis 26.48% of wing chord at that station. The aileron chord at its inneredge is nominally 24 cm, which is 28.96% of wing chord at that station.The main wing trailing edge has a nominal 8.14° angle of forward sweep.

The SkyQart's tail height is nominally 400.1 cm tall. The tall tailoffers improved headroom at the ramp/dock area underneath the tail, andensures that the autonomous robotic electric payload cart (EPC) canoperate on the dock without bumping heads of passengers on the empennageof the SkyQarts docked there. In addition, the tall tail offers a largewetted area above the wing that helps balance the drag of the wettedarea of the pod below the wing. The SkyQart's pod-shaped fuselage, theAFP, has a nominal outside diameter of 160.02 cm and a fineness ratio of2.93:1. Its shape coordinates are chosen for very low drag and itsautonomous rear hatch opening facilitates rapid loading and unloading ofthe EPC. Interference drag is minimized by having the cantilevered wingattach to the AFP using a molded-in large surface spar extension thatattaches in a removable fashion to the streamlined midline mono-strut ofthe AFP. The monostrut is important to the low drag of the SkyQart'sfuselage pod. The monostrut uses a GOE 460 airfoil shape, which issymmetrical. This airfoil is truncated at its trailing edge to reducewetted area. This airfoil is selected because its footprint onto the podroof is one that rapidly grows in width and maintains good width acrossmost of its attachment zone to the pod roof, thereby giving a strongbroad base for the attachment of the AFP via the monostrut to the wing'slower surface. The leading edge of that footprint extends along themidline of the AFP, forward of the main wing's leading edge, to a pointthat intersects the AFP's outer skin at a reinforced point that isnominally just 2.54 cm aft of the rear edge of the windshields. The GOE460 airfoil is deliberately chosen because it is a thick airfoil inorder to broaden and strengthen the monostrut attachment to the pod andto the wing. An optional way to strengthen the attachment of the AFP tothe main wing is by the addition of diagonal wing struts to themonostrut. Such diagonal wing struts are commonly used on the familiarCessna 172, for example. Such diagonal wing struts can reduce wingweight while imposing a penalty on drag. Diagonal wing struts are notused on the nominal embodiments of the SkyQarts presented herein.However, they could be used on some future alternative embodiments ofSkyQarts and still be encompassed by this patent. If used, there wouldbe one diagonal wing strut on the starboard wing and one on the portwing. Each of these would have an airfoil shape to its cross section andcould have its upper end attach to the main wing spar through an openingin the lower surface of the wing on or near the inboard edge of themotor nacelle. That strut could then have its lower end attachstructurally to the main longeron that is embedded into the sidewall ofthe AFP. The maximum chord of the monostrut GOE 460 airfoil is in thatportion near the top of the monostrut, where the airfoil is nominally36.2 cm thick. At the bottom of the monostrut, the GOE 460 airfoil isnominally 33 cm thick. The GOE 460 airfoil shape transitions into awider (spanwise) shape as it joins the lower surface of the wing, withfillet radii to reduce interference drag and to increase its grip on thewing structure. This wider shape continues into the tailcone andcomprises the forward portion of said tailcone. The tailcone isnominally 63.5 cm wide at the trailing edge (TE) of the wing, and thewaterline of the tailcone is positioned to intersect the wing so as toachieve the lower drag attained by a mid-fuselage wing arrangement. Thegradual tapering reduction of the tailcone's cross-sectional area beginsjust aft of the wing trailing edge. At the fuselage station thatcoincides with the rearmost edge of the rear hatch when the rear hatchis fully opened to 90°, the belly of the tailcone is nominally 198.2 cmabove the ground level, enabling a walk-under height adequate even fortall people. When docked, the walk-under height from the dock surface tothe lower skin of the tailcone at this same fuselage station isnominally 151.3 cm. This 151.3 cm is a height tall enough to allow eventhe tallest laden EPCs to drive on the dock underneath the tailcone withmore than 25.4 cm clearance.

The wing and empennage can be removed from the axisymmetric fuselage podfor maintenance, repair and replacement. The wing can likewise beremoved from the empennage and tail cone at a separation bulkhead in thetailcone just aft of the monostrut.

The propeller disc plane of the SkyQart propellers are both at thenominal fuselage station 81.3 cm aft of the datum, which datum is theexternal tip of the nose of the AFP. The propeller thrust axis of eachpropeller is nominally 211.2 cm above the ground. This ensures adequateground clearance for the propeller blades of nominally 152.4 cm radiusand enables the propeller thrust to help reduce wheelies on take-off.The propeller disc plane and ground clearance are different for thepropellers on the dual-AFP version named herein as the SkyQart III.

The SkyQart's main landing gear is equipped with wheelmotors that areactive in controlling its ground operations including take-offacceleration, speed and positioning. The main landing gear wheelmotorsalso have a programmable energy regeneration system that providesprecise and powerful anti-lock regenerative braking. The main landinggear legs attach to their shared crossbar trunnion through a sturdydropped arm that ensures that the landing gear legs do not scrape on theunderside of the dock during docking. Each main landing gear leg has aprogrammable electro-mechanical actuator system that both absorbslanding loads at a precisely controlled rate and controls ride heightand fuselage pitch angle. The active main landing gear offers a nominalmaximum travel of 65.02 cm from full down to full up, and theprogrammable absorption utilizes all 63.5 cm on each landing touch-downto provide comfortable landings with no bounce or rebound and withGRACE. Alternative embodiments of the SkyQarts may have a maximumlanding gear travel within a conceivable range of about 30 cm or more,about 50 cm or more, about 70 cm or more, about 80 cm or more or anyvalue between and including the maximum travel dimensions provided,though it is preferred that the maximum landing gear travel be thenominal interoperable 65.02 cm with a preferred range of 50-65 cmbecause this provides a long enough distance to gradually reduce theamount of deceleration experienced by passengers during a landingtouchdown and keep the leverage forces on the landing gear legs atmanageable levels while averting any scraping on the pavement of thebelly of the AFP. The controllable sink rate and landing gear travel aretemporally coupled with the retraction of the fast flaps and thereversal of propeller thrust to ensure full down force on the mainlanding gear tires within nominally 0.5 seconds of touch-down, whichenables the tires to provide maximum braking action against thepavement.

Each main landing gear tire is nominally 40.6 cm in diameter.Alternative embodiments of the SkyQarts may have a main landing geartire diameter within a conceivable range of about 30.5 cm or more, about35.5 cm or more, about 42 cm or more, about 46 cm or more or any valuebetween and including the tire diameters provided, while it is preferredthat the tire diameter be the nominal interoperable 40.5 cm because thissize provides enough size to contain an in-hub wheelmotor and to bearthe weight loads involved while still fitting underneath the dock duringdocking, and in addition is a diameter that is small enough to allowhigher RPM of its wheelmotor to provide more efficient power duringtake-off. Each main landing gear tire has a nominal interoperable widthof 12.7 cm. Alternative embodiments of the SkyQarts may have a mainlanding gear tire width within a conceivable range of about 10.16 cm ormore, about 14 cm or more, about 20 cm or more, about 25.4 cm or more orany width between and including the tire widths provided, but thepreferred tire width is the nominal interoperable 12.7 cm with apreferred range of 10-15 cm because this provides sufficient area to thetire contact patch to apply the power of the wheelmotor during take-offwithout causing excessive tire noise, weight or frontal drag. The mainlanding gear track width for SkyQarts I, II and III is nominally 262.36cm. Alternative embodiments of the SkyQarts may have a main landing geartrack within a conceivable range of about 220 cm or more, about 280 cmor more, about 300 cm or more or any value between and including themain landing gear track widths provided, while it is preferred that thewidth be the nominal interoperable 262.36 cm because this provides awidth sufficient to straddle the operation of the equipment in the dockservice bay, to stabilize the ground operations of the long wingedSkyQart in windy conditions and, combined with the position of theSkyQart wingtip, to prevent any possibility of propeller tip groundstrike during ground operations. The SkyQart's landing gear wheelbase isnominally 371.1 cm. Alternative embodiments of the SkyQarts may have alanding gear wheelbase within a conceivable range of about 250 cm ormore, about 350 cm or more, about 450 cm or more or any value betweenand including the landing gear wheelbase sizes provided, but it ispreferred that the landing gear wheelbase be the nominal interoperable371.1 cm with a preferred range of 320-380 cm because this providessufficient stability for ground operations and allows the large landinggear loads to be applied on the AFP at its reinforced hard points, whilebeing small enough to limit the weight and drag of the system. Thesenominal interoperable dimensions may change on alternative embodimentsif the interdependent components are likewise changed to be compatible.Each main landing gear leg is attached to and pivots on a large trunnionthat rotates in the starboard and port main landing gear pillow blockbearings which are integrated into the reinforced hard point structureof the AFP at a location just below the cabin floorboard and justforward of the rear hatch opening. The trunnions for the port andstarboard main landing gear legs interdigitate in a transverse tube toprovide load dissipation. The trunnion axis is nominally 50 cm aboveground during docking. Each main landing gear leg can swing through anarc of nominally 64° in normal operation, which provides a diagonallyaftward travel of the center of the tire contact patch of 79.8 cm and avertical travel of nominally 65.02 cm. Each landing gear leg is rigidlyattached to a trunnion that has a lever arm at the main landing gearpillow block bearing on the side of the pod, which arm operates along anarc fore-aft just inside the wall of the AFP's cabin area. The leverarms, in turn, are attached to an electrically controlled landing gearactuator that can precisely position the main landing gear leg at anyposition along its 64° arc of operation. There is a precise and requiredposition for the main landing gear leg during each of these operations:taxiing, take-off, cruise flight, landing approach, docking, andmaintenance. During landing approach, the landing gear is positioned atthe full down position and upon touch-down, its shock absorbing motionis precisely controlled by the fast-acting actuator to ensure tolerablejerk rates for the aircraft and occupants and to take full advantage ofthe relative long travel for the gradual absorption of landing loads.

In the SkyQart, the main landing gear wheel fairings must reduce drag asmuch as possible while still being able to accommodate the very long 640travel of the landing gear leg without striking the pavement on initialtouch-down. Due to alignment when the landing gear is in the full downposition during landing approach, it is necessary to truncate the aftportion of the wheel fairing so that it will not strike the ground uponlanding. The wheel fairing shape is derived from a scaled-down low-dragversion of the AFP of the SkyQart. The wheel fairing is clocked onto thelanding gear leg so that its drag is minimized with the landing gear inthe fully retracted position for cruise flight. The highly tilted angleof the wheel fairing when the landing gear is in the full-down positionwill increase total drag and this is intended to enhance the aircraft'scapability for making steep landing approaches that minimize communitynoise impacts. Some versions of the wheel fairing may have hinged rearportions that fair with the forward section during cruise flight, butthat are actuated to retract upward to increase drag during finalapproach.

The Qusheat ride control seat is an electro-mechanically actuatedcushioned seat that is used as standard equipment in all SkyQarts toenhance ride quality for passengers. Similar to the technology ofnoise-cancelling headsets, the Qusheat ride control seat has apro-active anticipatory electro-hydraulic actuator that counter-acts thegusts from turbulence that would otherwise create an uncomfortable orbumpy ride. It is an integral part of the passenger seats used in manybut not all SkyQarts.

Standard human dimensions⁴ along with commonly accepted guidelines forbusiness class airline seating were used to size the seating spaceinside the SkyQarts. The seats are sized so as to allow each seat tohave port and starboard armrest. A retractable lightweight, thin butrigid, translucent plastic sheet between the side-by-side seats can befitted onto the EPC to serve as personal protective equipment and/or toenhance privacy for passengers. The bottommost part of the passenger'sseated torso is nominally 16.5 cm above the EPC surface with the seatfoam compressed. From this bottommost part of the passenger's torsoseated on the EPC inside the AFP, a 97.8 cm diagonal dimension to thetop of the passenger's head provides the space necessary for a 188 cmtall man of 95th percentile to have adequate cabin headroom inside theSkyQart. Alternative embodiments of the SkyQart that use larger orsmaller diameter AFPs will need their cabin floor and EPC seatdimensions to preserve this 188 cm in order to provide adequate headroomfor the 95^(th) percentile of the population and thereby serve thegeneral public's transportation needs.

The SkyQart's automatic rear hatch opens autonomously just prior to theloading and unloading of the SkyQart during docking. The SkyQart's cabinfloor is equipped with shallow grooves to help guide an EPC's tires intothe correct latching positions. The cabin sidewalls of the AFP arereinforced at the locations of the four solenoid-actuated latching pinsthat secure the laden EPC to the cabin structure, so that said solenoidscan be securely structurally mounted to the AFP. During the loading ofan EPC into or out of the SkyQart at the dock, the SkyQart's cabinfloorboard height is maintained in alignment with the dock height byboth the active main landing gear and by a set of solenoid activatedshear pins that extend from the dock face into the aft face of thefloorboard of the SkyQart.

The portion of the AFP aft of the rear hatch is a foam filled flotationdevice with removable modules of foam to allow different internal volumespace. This comprises one component of the closed flotation system.

The nominally 18° tilt-up angle of the rear hatch clears the docksurface and landing gear. The front of the rear hatch has a nominalinteroperable outside diameter of 156.8 cm which, with its 2.54 cm thickwalls affords a 151.7 cm inner diameter opening for loading payloads.The rear hatch opens on a nominally 20.3 cm long hinge upward at an 18°angle, toward the left wing, such that the hatch clears the main landinggear (including the wheelpant) and clears the dock surface as well asthe lower surfaces of the tailboom, and wing trailing edge. Its openingswing also clears the inboard flap hinge fins, which have to be placednominally 57.3 cm outboard of the flap root in order to not obstruct thehatch movement. The rear hatch forward edge in the nominal SkyQart AFPis at fuselage station (FS) 278.9 cm, as measured from the datum that isthe external forward-most tip of the nose of the AFP. This location ofthe hatch is chosen because it offers a large opening for loading andbecause it places the seam of the hatch aft of the smooth forebody ofthe AFP so as to preserve its low drag coefficient.

The SkyQart I has each of its wingtips tilted upward at a nominalinteroperable angle of 8.84° while the SkyQart II has its wingtipstilted downward at a nominal interoperable angle of 11.87°. Thesedifferent angles for the wingtips enable these two different aircraft tohave overlapping wingtips when they park wingtip to wingtip at the dockat the SkyNest. Angles smaller than 8.840 or larger than 11.87° may beused, but those alternative embodiments would adversely affect eitherwingtip clearances or aircraft spiral stability, respectively.

The wing leading edge at the midline of the fuselage is nominally atfuselage station (FS) 179.05 cm where its chord is 142.3 cm. Other FSlocations could be used in alternative embodiments but would thatadversely affect the aircraft's center of gravity, wing attachmentstructure or propeller tip to cabin clearance dimensions. The main winguses a unique airfoil shape that is modified from that of the GA W2airfoil. The lower surface of the wing is a minimum of 30.85 cm abovethe top skin of the AFP at the midline of the aircraft. Alternativeembodiments that use larger or smaller dimensions for this distancebetween the wing and the AFP could be used in the conceivable range offrom 15 to 47 cm, but these would likely entail increases in weightand/or interference drag.

The SkyQart cabin floorboard during docking is set to a standard 47 cmfrom the top of its cabin floorboard to the ground or pavement level.The cabin floorboard is nominally 2.54 cm thick.

The length of all moment arms used in the computation of the e.g. aremeasured from the datum, which is at fuselage station (FS)=0.00, andwhich is located at the external forward-most tip of the AFP.

The ballistic recovery system is packaged in a nominally 71.1 cm×30.5cm×19.0 cm box and is a rocket-propelled vehicle parachute. Theballistic recovery system weighs a nominal 27.2 kg.

The active main landing gear maintains the height of the cabinfloorboard during loading. The main landing gear legs can move upward soas to squat to lower the fuselage pod belly to just above ground levelfor off-loading an EPC onto a 244 cm long ramp in cases where no dock isavailable. The pod belly needs to not touch the ground or pavementduring a full jounce movement of both main landing gear, as occurs inhard landings or parachute touch-downs. Keeping the pod belly low downaverts wheelies, makes docks less costly, eases off loading, addsstability and enhances ground effect. The pod belly lowermost exteriorsurface has a nominal interoperable ground clearance of 21.6 cm aboveground level during ground operations.

SkyQart windshields are above the mid-fuselage waterline. Thewindshields have tight seams between their window-frames and the AFP.The nominal measurements for the windshields are as follows: The forwardedge of the windshield is at FS 39.2 cm where the pod outside diameteris 69.8 cm. The aft edge of the windshield is at FS 148.2 cm where thepod outside diameter is 137.4 cm. All corners of both windshields have a5.08 cm radius to avoid stress risers. The two 71.12 cm diametercircular side windows of the AFP serve as emergency exits. Each is heldin place by an internal, replaceable, pull-to-remove perimeter adhesivetape strip. Their round shape and inner perimeter frame safe-guard themagainst being pressed, blown or sucked-out into the nearby rotatingpropeller tips. The windows each have one or more internal pull gripsthat enable a passenger of ordinary strength to use his or herfingertips pull the window inward to remove it, after they easily peelaway its perimeter adhesive tape strip. The peelable perimeter adhesivetape strip may be made of metal, plastic, duct tape or other material.On the exterior surfaces around these round windows, a customizedextruded rubber seal is pressed and lightly glued into the perimeter gaparound the circular side windows to produce a flush external skin thathelps to preserve the low-drag airflow on the outer surfaces of the AFP.

Using EPCs, the interior of the SkyQart can accommodate a variety ofpayloads. The EPC can be configured to carry one, two or three seatswith small, accessible baggage containers suited to the number of seats.The aft baggage rack limits the seatback recline angle, but this istolerable for a mass transportation vehicle that typically makes onlyshort-range trips of less than one hour duration. Alternatively and withmodified cargo hauling attachments, the EPC can be fitted to carry amed-evac litter⁵, a wheelchair, scooter, folded bicycles, generator, apair of 208.2 liter (55-gallon) drums, lumber, plywood, sheetrock, solarpanels, fuel cans, pets in cages or kennels or various sizes of cargobins.

A cargo version of the SkyQarts I, II and III can be fitted with anominally 0.61 m cylindrical extension of its AFP, making it the cargoAFP. That extension firmly attaches with fasteners to the standard AFP'srear hatchline, with flush alignment of the external skin contours ofthe AFP. The trailing edge of this cylindrical extension is an exactclone of that of the standard AFP, having the same dimensions andfasteners that are at the rear hatchline of the standard AFP. Thesefasteners provide a sturdy and flush attachment of a standard AFP rearhatch to the aft face of the cylindrical extension to make it a CAFP.

The retractable landing gear in the nose of the laminar pod is afree-swiveling type that provides up to 22.4 cm of nominal interoperableupward travel from its fully extended position. Alternative embodimentsof the SkyQarts may have a nose landing gear travel within a conceivablerange of about 12 cm or more, about 18 cm or more, about 24 cm or more,about 32 cm or more or any value between and including the nose landinggear travel provided, while it is preferred that the nose landing geartravel be the nominal interoperable 22.4 cm with a preferred range of20-25 cm because this provides a relatively long distance over which togracefully absorb the vertical loads of landing while keeping the totalweight and size of the nose landing gear to a size that can retract andfit inside the nose of the AFP. The nominal interoperable outsidediameter of the nose tire is 30.5 cm. Alternative embodiments of theSkyQarts may have a nose tire outside diameter within a conceivablerange of about 22 cm or more, about 28 cm or more, about 34 cm or more,about 42 cm or more or any value between and including the nose tireoutside diameters provided, while it is preferred that the nose tireoutside diameter be the nominal interoperable 30.5 cm with a preferredrange of 28-34 cm because this provides a size that can bear theanticipated loads on the nose landing gear and that is small enough tofit inside the space available for the retractable nose landing gear inthe nose of the AFP.

The horizontal and vertical tail volumes are deliberately larger thanthose commonly used in order to ensure brisk and agile control under allflight conditions. The Horizontal Tail Volume coefficient for theSkyQart I and II is nominally 0.895 and the Vertical Tail Volume (Vv)coefficient is nominally 0.064, when using a nominal wing area of 11.4sq m and a nominal wing m.a.c. of 188.5 cm with a mid-range e.g. TheVertical Tail Volume coefficient can be expected to act as if it were0.07 or more due to the end-plate effect of the “T-tail”, which enhancesthe rudder effectiveness, along with the fact that this vertical tail isvery tall and thereby operates in undisturbed air. For comparison: theBeechcraft Baron with a large vertical tail has a Vv value of:16×22.7/199.2×38=0.048, while having nearly the same distance betweenits two propeller thrust lines.

At the flap root, an 18.6 cm chord distance of exposed flap is visibleon the upper surface of the wing. The flaps on each wing have a nominaltotal span 788.0 cm, which is 71.8% of the exposed wingspan of 1097.3cm. The inner flap hinges are placed a nominal interoperable 57.3 cmoutboard of the flap root in order to clear the swing opening of therear hatch of the AFP. The cabin floor is nominally 25.4 cm above thelowest point on the pod's external belly skin, which is 21.6 cm aboveground level. Interoperability relies upon the dock at all SkyNestsbeing set at a standard of 47.0 cm above ground level.

For comparison, the twin engined Beechcraft Baron's propeller thrustaxes are 353.0 cm apart, while the SkyQarts I & II have larger diameterpropellers whose thrust axes are nominally 366.4 cm apart.

The SkyQart's rear hatch and tailcone have closed, foam-filled orair-filled flotation spaces that are part of the closed flotationsystem, as are the other hollow foam-filled spaces in the AFP, wings,empennage and tail cone that are unoccupied by equipment.

A Faraday cage surrounds the battery pack in order to safely contain itshigh voltage in the event of a ditching into water and is part of itsfire-resistant enclosure.

The rationale for the SkyQart's T-tail design is derived from extensiveaeronautical design considerations. The SkyQart must have a tail thatensures brisk, authoritative pitch and yaw control at all times, mostespecially during slow flight at or below its 24 m/sec nominalinteroperable liftoff and touch-down speeds, when the dynamic pressureis only about 34.2 kg/m². That means that its tail surfaces must be keptlarge enough to be effective at low airspeeds, even though thatincreases wetted area and drag. The potential for asymmetric thrust andyaw during slow flight with one motor inoperative in a twin motoredSkyQart demands a relatively large vertical fin and rudder. The need toabruptly execute a nose-up pitch change at just the right moment duringtake-off, especially in a SkyQart that is taking off downhill, alsodemands a large and effective horizontal tail, aided in part by a surgein power applied to the active main landing gear wheelmotors to generatea torque that helps produce a desired wheelie-like nose-up pitchattitude at the instant of lift-off.

Using a T-tail on the SkyQart has the benefit of placing substantialwetted area above the thrust line, which can help offset the largewetted area drag that exists below the thrust line due to landing gearand AFP surfaces. At the loading dock, a high T-tail keeps well abovethe cart movements and heads of passengers and their packages or otheritems that might otherwise have to duck under a low tail.

T-tails help ensure that the airflow across the vertical and horizontaltail is not ‘blocked’ or cavitating from upstream turbulent flows comingoff of a stalled wing or a windmilling prop. By keeping the elevator upand out of the propeller slipstream, the pitch trim changes that occurwith abrupt changes in thrust settings are minimized. Likewise, theT-tail minimizes the irregular or turbulent inflow that can occur attouch-down and in ground effect at high nose-up attitudes due towing/flap downwashes that strike the ground and then deflect upward intothe tail surfaces. Ideally, the forces generated by the tail surfacesare predictably related only to airspeed and control surface deflectionangle and NOT to any other secondary effects.

The T-tail confers an ‘end-plate effect’ to the vertical tail that addssome 5-10% to its effectiveness. Unlike the conventional low-mountedhorizontal tail, the high-mounted horizontal T-tail also does not blockor blank the upward airflow to the vertical tail during a high angle ofattack sink or spin.

The T-tail's disadvantages are that it is heavier and has a morecircuitous, complex path for its elevator control cables. This is not aproblem when the SkyQart aircraft is fully autonomous with fly-by-wireremote actuators in the tail and needs aft weight increased for e.g.purposes. The weight added by a T-tail can be mitigated somewhat by thestructural efficiency of using a laminar flow airfoil of greaterthickness to chord ratio (e.g. 15% or more) for the vertical tail, alongwith larger than usual chords at the points where the surfacesintersect. There have been some instances where the T-tail has beenblanked due to the stalled burble airflow coming off the forward wing.The likelihood of that is much reduced when the forward wing is one ofhigh aspect ratio, is far forward of the T-tail, and, when thenegligible control latency of autonomous flight ensures that the mainwing never allowed to stall. Augmenting elevator authority with a blastof propeller thrust is a benefit for low-set horizontal tails ascompared to T-tails, but it also causes weird unpredictability in powerinduced trim settings, especially during the flare to land. AnotherT-tail disadvantage is that, being high above the ground, it is moredifficult to inspect and service.

The nominal planforms of the tail surfaces are chosen to fit optimumdesign practices. Low aspect ratio wings (or tails) have the benefit oftolerating higher angles of attack before stall occurs. However, lowaspect ratios have more drag and with less span, they extend across asmaller region so that areas blanked by localized stalled airflow couldbe more of an issue than with a larger span that extends outside theregion of blanking. Sweep angles of the tail surfaces can reduce theirlift coefficient and drag, but this is a relatively minor ˜5% factor ifthe sweep angles are kept below 15°.

The tailcone length and tail surface area are chosen to comply withreasonable guidelines for the tail volume coefficients, the metrics thatpredict tail surface effectiveness⁶. A horizontal tail volumecoefficient, V_(H), is computed as:

V_(H)=S_(H)×L_(H)/S_(W)×m.a.c., where S_(H) is the horizontal tailsurface area and L_(H) is the length or distance from the horizontaltail's aerodynamic center to the aircraft's e.g. location. Thehorizontal tail's aerodynamic center is conventionally located at 25% ofits mean aerodynamic chord. The surface area of the wing is denoted byS_(W) and the m.a.c is the main wing's mean aerodynamic chord.

The vertical tail volume coefficient. V_(V), is computed as:

V_(V)=S_(V)×L_(V)/S_(W)×b where S_(V)=vertical tail area, L_(V) is thediagonal length or distance from the vertical tail's aerodynamic centerto the aircraft e.g., S_(W) is the wing surface area and b is thewingspan. Both V_(H) and V_(V) must be larger than usual for theSkyQart, to ensure that it will have sufficient capability in strongcrosswind landings and full and brisk control authority during its slowflight modes, landing flare and in steep approaches with windmillingprops. The need for larger tail volume coefficients is eased somewhat bythe SkyQart having fully autonomous flight controls with negligiblecontrol latency. This may allow alternative embodiments of the SkyQartto use smaller tail surfaces.

The tail volume coefficients, V_(H) and V_(V), for the SkyQarts I and IIare scaled in relation to the known values for successful historicaltwin engine aircraft. V_(H) for general aviation twin-engine aircraftare in the range of 0.8 to 0.9. The SkyQart I and II have a nominalV_(H) of 0.895. This value is computed upon an S_(H) value for theSkyQart I and II of 2.8 sq m and an L_(H) value of 430.4 cm measureddiagonally from the e.g. to 25% of the mean aerodynamic chord of thehorizontal tail. The mean aerodynamic chord of the horizontal tail(m.a.c.) is a nominal 75.8 cm.

The SkyQarts I & II nominal wing area, Sw, is 11.4 sq m and the wingmean aerodynamic chord (m.a.c.) is nominally 118.5 cm. The leading edgeof the wing m.a.c. is located at a nominal 173.9 cm aft of the datum,which is taken as the forward-most point on the external surface of theAFP.

The V_(H) of both the SkyQart I and II is a nominal 0.895. Forcomparison, the V_(H) of the Luscombe is 0.442, and of the Navion is0.692, while general aviation twins & turboprops have V_(H) values of0.8-0.9. For the vertical tail coefficient, V_(V)=Sv×Lv/Sw×b, and thiscomputes as 0.0640, where b is 11.0 m, Sv is 2.1 sq m and Lv diagonallyis 377.2 cm.

The mean aerodynamic chord of the vertical tail is a nominal 128.4 cmwhich means that 32.1 cm is the aerodynamic center of the vertical tail.

The horizontal tail airfoil section is the GAW2 with a 12% thickness tochord ratio.

The vertical tail airfoil section is the NACA 63-015A airfoil.

The tire size for main landing gear is nominally a 40.6 cm outsidediameter.

Tire size for nose tire is nominally 30.5 cm outside diameter.

The maximum jounce travel for the main landing gear tire from its staticposition when parked on the pavement ramp is a nominal 18.5 cm.

The SkyQart wing's lower surface at the aircraft midline is a nominal30.9 cm above the roof of the AFP. The vertical distance from the thrustline to the roof of the AFP is 29.6 cm. The SkyQart's main wing sparshear-web height at the aircraft midline is nominally 21.3 cm. The mainwing's main spar shearweb is located at a nominal 32.48% of the wingchord.

The tailcone shape can be one of circular cross-section or slightly ovalwith the oval's long axis oriented vertically, since the vertical loadson the tailcone are likely much larger than the side loads. The tailconecross-section must be large enough to contain the elevator and ruddercontrol parts.

The appearance of the tail planform shapes affects the esthetics of thewhole aircraft, and they must be proportionate and not outsized toengender confidence in the design.

The nominal interoperable SkyQart I and II each have two propellers thatare each mounted on a separate propeller motor that is mounted to aseparate nacelle. There is a port nacelle and a starboard nacelle andeach nacelle is on an opposite side of the AFP. These nacelles areattached to the leading edge of the main wing. The thrust axes of thesetwo propellers are nominally 3.66 m apart. Alternative embodiments ofthe SkyQart I and II may have a number of propellers with a conceivablerange of two to six but the preferred nominal interoperable number ofpropellers is two. Propeller spinners are both of a nominal 40.6 cm basediameter covering the electrically controlled propeller hubs of theultra-quiet 7-bladed propellers.

The three-seat variant of the EPC loaded into a SkyQart I or II isintended to be used in the development phase of these aircraft in orderto allow the occupant of the front seat to manually pilot a SkyQart asan optionally piloted vehicle (OPA) using conventional stick and ruddertype controls. Such manual piloting is anticipated to be the standardfor early implementations of QUAD, both for passenger and cargo service,while fully autonomous capabilities are undergoing maturation andcertification.

The SkyQart uses a standard of 600 volts for its battery pack whosestandard outside dimensions are 8.9 cm H×66.0 cm W×101.6 cm L. Thiscomprises the standard battery pack or SBP for the QUAD system.Alternative sized embodiments of this battery may be used, but thatwould entail changing the standard dimensions of many other componentsthroughout the QUAD system. The SBP is mounted just under the SkyQart'scabin floor. It can be easily removed from the SkyQart by sliding it outalong its heavy-duty extensible drawer slides⁷. It can also be chargedduring docking with a DC fast-charge port located at the SkyQart's rearhatch opening. This port engages automatically as the precisionpositioning system (PPS) positions the SkyQart at an aircraft dockingstation.

The SkyQart's core equipment requirements, by name, are the following:

an ultra quiet propeller system with electric hub that offers rapidpitch change

an active main landing gear

at least two smart, ultra-quiet propellers that also act as spoilers

a fast flap system with double-slotted semi-Fowler flaps

a solenoid-actuated pin-latching system system

a networked situational awareness system at SkyNests

a precision positioning system with line-following software

a Standard Battery Pack (SBP) with a battery management system

a landing gear wheelmotors with regenerative braking

an AFP: axisymmetric fuselage pod

a peelable window frame with two pull-in emergency exit windows

an autonomous control system with negligible control latency

an automatic rear hatch on the rear portion of the AFP

an ELT: emergency locator transmitter

a Faraday cage around each battery pack

a BRS: ballistic recovery system comprising a parachute for a SkyQart

a robotic battery swap system using a robot arm

an EPC: electric payload cart

a Qusheat ride control seat: Autonomous passenger seats with ridecontrol

a closed flotation system, wherein unused volumes in the SkyQart aresealed watertight for flotation

a cargo axisymmetric fuselage pod: the optional cargo AFP that gives a61.0 cm cylindrical extension to the AFP

a lightning strike protection (LSP) of embedded metal mesh in the AFPwall

a retractable nose wheel landing gear

a DC fast-charging port at its rear hatch

a lightweight composite airframe

a T tail configuration with large tail volume coefficients

a forward swept laminar flow main wing

a monostrut wing attachment to its AFP

an OPA: Optionally Piloted Aircraft controls (stick, rudder, throttle,flaps)

The SkyQart III

The SkyQart III is an important component to this invention. It is thelarger, 6-passenger version of the SkyQart. It differs from the SkyQartsI and II in having two identical AFPs, each of which is identical to theAFP used on the SkyQarts I and II except that the starboard AFP in theSkyQart III has its rear hatch open toward the starboard wing tip. Thecentral axes of the AFPs of the SkyQart III are nominally 4.57 m apartin order to fit the equal spacing between the SkyNest aircraft dockingstations. The nominal embodiment of the SkyQart III has threepropellers, each driven by a separate motor on a separate nacelle on theleading edge of the wing. Alternative embodiments of the SkyQart III mayhave a number of propellers with a conceivable range that is three ormore, four or more, five or more, six or more or any number between andincluding the numbers provided, while it is preferred that the number be3 propellers because this provides low noise with a broad acceleratedwake of increased airflow over the wing surface for blowing on the fastflaps, while also limiting the weight and complexity of the aircraft.The SkyQart III has a nominal interoperable maximum gross weight of 1450kg. Alternative embodiments of the SkyQart III may have a maximum grossweight with a conceivable range of about 1350 kg or more, about 1450 kgor more, about 24 cm 1650 kg or more, or any weight between andincluding the maximum gross weight provided, while it is preferred thatthe maximum gross weight be the nominal interoperable weight of 1450 kgwith a preferred range of 1400-1500 kg because this limits the amount ofnoise by limiting the amount of installed power needed for a sufficientrate of climb, while preserving a good payload weight and fitting thecapacities of the tire sizes used. The SkyQart III has a nominalinteroperable wingspan of 15.37 m. Alternative embodiments of theSkyQart III may have a wingspan with a conceivable range of about 14 mor more, about 18 m or any wingspan between and including the wingspansprovided, while it is preferred that the wingspan be the nominalinteroperable 15.37 m because this provides a low span loading thatenhances the rate of climb on limited power without undue increases inwing weight, while also limiting the spanwise distance necessary fordocking at the SkyNest dock. It will be noted that the SkyQart III hassubstantially longer wingspan than that of the SkyQart I or II. TheSkyQart III has a nominal interoperable wing area of 18.96 sq m.Alternative embodiments of the SkyQart III may have a wing area with aconceivable range of about 16 sq m or more, about 19 sq m or more, about21 sq m or more, any wing area between and including the wing areasprovided, while it is preferred that the wing area be the nominalinteroperable 18.96 sq m with a preferred range of 18-20 sq m becausethis provides a low wing loading that reduces the landing speed withoutundue increases in wetted area. The nominal interoperable wing loadingof the SkyQart III is 76.5 kg/sq m because this reduces the landingspeed without undue increases in wetted area. The nominal SkyQart IIIhas a maximum height of 402.8 cm with a horizontal tail area of 4.9 sq mand a vertical tail area that totals 4.28 sq m. The nominal SkyQart IIIhas a horizontal tail volume coefficient V_(H) that is nominally 0.926with a range of 0.8 to 1.1. Its vertical tail volume coefficient Vv isnominally 0.057, with a range of 0.05 to 0.09. These are relativelylarge numbers so that the SkyQart III can have enough yaw and pitchcontrol authority to offset the large spanwise polar moment of inertialcaused by its two axisymmetric fuselage pods as well as its forwardcenter of gravity that inhibits wheelies on take-off. The SkyQart IIIemploys extensive parts commonality with the standard SkyQarts I and II,including its axisymmetric fuselage pods, landing gear, seating,windshields, hatch, battery packs, mono-strut, floorboards, pin-latchingsystem, outboard wing panels, controls, and ballistic recovery systemparachutes.

By hauling three passengers in each pod, each flight of the SkyQart IIIcan carry six passengers in all, if the average weight of thosepassengers is less than nominally 70 kg. When carrying six passengers,total baggage weight is restricted to nominally 13.6 kg. The nominalmaximum payload for the nominal SkyQart III is 488 kg, with a limit of244 kg per AFP. However, this payload may be increased to as much as 612kg with a limit of 306 kg per AFP in future alternative embodiments ofthe SkyQart III if it can be done while preserving the SkyQart II'sESTOL and ultra-quiet take-off performance necessary for operations atSkyNests. Alternative embodiments of the SkyQart III may have a payloadwith a preferred range of 600-650 kg. The wing tips of the nominalembodiment of the SkyQart III are tilted upward from the horizontal atan angle of 9.58° to enable it to park at the dock of a SkyNest with itswingtips overlapping those of the other SkyQarts I or II. Thisoverlapping provides more room for docking spaces and thereby increasesthe capacity of the SkyNest.

The roof of the standard battery pack is nominally set 4.76 mm below thebottom surface of the cabin floor in all SkyQarts. This allows 3.175 mmthicker dock surface that is 28.58 mm thick with still a 0.79 mmclearance for the battery pack to slide under the bottom surface of thedock.

The nominal interoperable SkyQart III has a 14.0 cm thick horizontaltail with a 13% thickness to chord ratio based on a 107.4 cm chord. Itshorizontal tail is 402.8 cm above ground level. There are nominally 4.57m between the SkyQart III's nose-tire centerlines. These nominaldimensions are deterministic of the dock ceiling height and distancebetween aircraft docking stations at the SkyNest, respectively.

Each outer main wing of the nominal SkyQart III has a 6.2° forward sweepof its trailing edge and has 5.66 sq m of wing area, which, when addedto the 7.63 sq m wing center section creates a total wing area of 18.96sq m. Compared to the SkyQart I and II, the SkyQart III has a largerwingspan of that is a nominal interoperable 15.37 m which gives anominal interoperable aspect ratio of 12.46:1, computed as the result ofwingspan squared divided by wing area. Alternative embodiments of theSkyQart III may have a wing aspect ratio within a conceivable range ofabout 10 or more, about 12 or more, about 14 or more or any aspect ratiobetween and including the aspect ratios provided, while the nominalinteroperable aspect ratio of 12.46:1 is preferred because it providesan energy efficient airframe with reduced induced drag and a manageablewing weight, and reduces the demand for climb power and thereby avertsexcessive noise.

The nominal SkyQart III has 4.91 sq m of horizontal tail.

The nominal SkyQart III has 2.14 sq m of area on each of its verticaltails, which together combine to provide a total of 4.28 sq m ofvertical tail area.

The nominal SkyQart III has three propellers, each of 3.048 m diameterand each mounted on its own nacelle forward of the main wing. Thecentral of these three propellers is mounted in the midline of theaircraft on a nacelle that attaches to the center section of the mainwing. The central propeller has a thrust axis that is nominally 223.0 cmabove the ground when the aircraft is parked in its static position atgross weight. The central propeller disc plane is at fuselage station94.56 cm aft of the datum. The two outer propellers have their thrustaxis slightly higher, nominally at 228.1 cm above the ground. The twoouter propellers of the SkyQart III have their propeller disc planelocated at fuselage station 103.73 cm aft of the datum. The two AFPs ofSkyQart III can each contain an EPC that hauls one, two or three seats,thus providing for a maximum capacity of six passengers.

Each of the two AFPs of the SkyQart III has a nose-tire plus port andstarboard main landing gear tires. Having two AFPs helps to preserveprivacy and serenity in ride-sharing flights, yet with mutual consentthese two AFPs can share communication via an intercom.

The SkyQart III has a large blown flap span, with a double slotted fastflaps system on both the wing center section as well as on the left andright outboard wing panels.

All SkyQarts have a 21.6 cm belly ground clearance, a standard 47.0 cmcabin floor height and nominally 198.1 cm of headroom under the belly ofthe tailcone at the fuselage station that coincides with the rearmostedge of the fully opened rear hatch.

Alternative embodiments of the SkyQart III still fall within theconcepts and processes of this QUAD system patent, with dimensions andweights that differ from the nominal embodiment presented herein,provided that these alternatives are capable of ultra-quiet ESTOL andcan still interoperate autonomously with compatible EPCs, RDCs, docksand SkyNest facilities.

Overlapping Wingtips

Overlapping wingtips are an important component to this invention.During high capacity operations when the SkyNest dock is heavilyoccupied, the dispatch software known as the networked situationalawareness program for QUAD operations keeps track of whether an arrivingSkyQart is of type I, II or II and directs the arriving SkyQart to anappropriate aircraft docking station where its particular type ofwingtip can overlap that of the adjacent docked SkyQart, and therebymake more efficient use of the docking stations. When the operations ata SkyNest are of lower volume causing there to be many vacant aircraftdocking stations, these overlapping wingtip-matching requirements can beless rigorously enforced.

The overlapping of SkyQart wingtips saves dock span and thus enables asmaller size of land parcel for the SkyNest as well as a greater numberof SkyQarts to operate there. When a nominal SkyQart II and SkyQart Idock with overlapping wingtips, side by side in alignment with thedock's battery swapping pathways, their nose-tires are placed 9.144 mapart and this results in their combined spanwise dimension consuming atotal dock span of 20.14 m. In contrast, when two SkyQart I's or twoSkyQart's II dock side-by-side in alignment with the dock's batteryswapping pathways, they must do so without overlapping wingtips,resulting in their nose-tires being placed 13.7 m apart. This largerseparation results in their combined spanwise dimension consuming atotal dock span of 24.73 m, nearly 5 meters more dock space thanconsumed by the overlapping wingtips of a pairing of SkyQarts I and II.If each SkyQart is configured to carry three passengers, then theefficient, overlapping docking of two dissimilar SkyQarts achieves apassenger density of six passengers in 20 m of dock span, equating to3.33 m of dock span for every passenger. If the less efficient dockingof two identical SkyQarts with no wing overlap is similarly examined, itresults in six passengers in 24.73 m of dock span, equating to 4.12 m ofdock span for every passenger. The overlapping wingtips thus provide aroughly 25% improvement in dock efficiency. Similarly, when an ideal mixof SkyQart I, II and III are docked side-by-side in alignment with thedock's battery swapping pathways, as shown in FIG. 4, the total combinedspanwise dimension of that dock span consumed is 33.76 m. If each AFP ofthese three SkyQarts carries three passengers, this example results intwelve passengers in 33.76 m of dock span, which equates to only 2.81 mof dock span per passenger.

The Acceptable Noise Sphere

The acceptable noise sphere is an important component to this invention.Aircraft noise emissions radiate spherically outward in all directionsbut are of larger amplitude in some directions than others. The radialdirection outward from the vehicle along which the emitted noise is ofmaximum amplitude is herein defined as the azimuth of maximum noise.Along that azimuth, there is a definable radial distance at which theemitted aircraft noise will be quiet enough to be tolerable to 90% ofneighbors who live adjacent to an airport. Extensive airport noisesurveys in both Europe and the USA indicate that the quiet-enough noiselevel for those who live adjacent to airports, on whose surface aircrafttake-offs happen frequently and at night, averages a continuous noiselevel of 48 dBA or less at the airport boundary. This continuous 48 dBAclosely approximates the surface continuous noise level at which, onaverage, only 10% or less of airport neighbors reported being highlyannoyed. The FAA and other agencies generally consider ascommunity-acceptable (quiet-enough) noise levels that cause no more than10% of airport neighbors to be highly annoyed. In the QUADtransportation system, the aircraft noise emissions from its SkyNestsmust be acceptable to quiet residential communities. The noise of tiresrolling on pavement can be a significant contributor to the noiseemitted during take-offs and landings. One study of the tire noise oftowing a 658 kg small aircraft with tricycle landing gear with tiresthat were all longitudinally ribbed Goodyear Flight Custom III tire500-5 6 ply PN: 505c66-5 aircraft tires rolling on smooth asphalt at 55mph (with no engine or propeller noise) found that such tire noise mayreach 60 dBA at a 30.48 m sideline, which is equivalent to 57.64 dBA ata 40 meter sideline distance. Similarly, a study of drive-by noise of anelectric-powered car, a Chevrolet Bolt with 4 wide tires of MichelinEnergy 215/50/R17, driving at 55 mph on a freshly smoothed asphalt roadin a no wind condition with an ambient noise level of 44 dBA, revealed apeak drive-by noise of 55 dBA at a 40 meter sideline. The standards tobe set for SkyNest noise can also be derived from studies of its healtheffects' and the current regulatory limit in 36 CFR Ch. 1 (7-1-10Edition) for machine noise (e.g. generators) in National Parks⁹, whichis 60 dBA continuous noise at a 15.24 m sideline distance. This isequivalent to 51.6 dBA at a 40 m sideline. This 51.6 dBA continuousnoise is a rigorous limit that can serve as a benchmark for preservingthe serenity in quiet residential neighborhoods. The tolerance for noiseduring sleeping hours at night becomes even more stringent; 24 dBAmeasured indoors is the level that 10% of respondents found highlyannoying. Annoyance also rises substantially if there are many flightspassing overhead during sleep time. Accordingly, there is a noise metricknown as the Lden or sound “level day, evening and night” in which ameasured noise level is penalized by adding 10 dBA during the time of23:00 to 07:00 and is penalized by 5 dBA during the time of 19:00 to23:00. A continuous noise level of 48 dBA is equivalent to 54.7 dBALden, which is the noise level that, on average from several studies,caused 10% of people living near an airport to be highly annoyed. Noiselevels of drive-bys and fly-bys are commonly measured as L_(eq), whichis the equivalent sound level averaged over a specified period of time.If measured using the A scale, then the L_(eq) metric becomes LA_(eq).If the LA_(eq) is the average sound level over a 5 second period, suchas a fly-by or drive-by event, then it is expressed as LA_(eq), 5 s.

From the foregoing, and the goal of ensuring community acceptable noiselevels from the QUAD system, a nominal acceptable continuous noise levelof 48 dBA is herein adopted as a standard for use in the depiction ofthe perimeter of the acceptable noise sphere in the Figures presented inthis patent. In addition, a maximum allowable noise level at theboundary of a SkyNest is 55 dBA LA_(eq), 5 s.

The acceptable noise sphere is simply a circular two-dimensionaldepiction of a three-dimensional sphere whose radius is that at which anaircraft's noise emissions along its azimuth of maximum noise wouldequal or exceed 48 dBA L_(eq) as measured from an unobstructed vantagenear the ground (surface) level of the airport or neighborhood. Thisstandard for the noise sphere can be applied to guide the operations,site and size of the SkyNests used in the QUAD system. The perimeter ofthe noise sphere depicts the boundary of a theoretical 48 dBA noiselevel as if it were emitted in all directions, even though it istypically only emitted along the azimuth of maximum noise. Noise levelsas one approaches the center of the acceptable noise sphere becomeprogressively louder than 48 dBA. The noise sphere provides a usefultype of ruler, a conservative guide tool to help make sure that annoyingaircraft noise levels are consistently kept within the boundaries of theSkyNest.

The radius of an aircraft noise sphere depends upon the power settingand the aircraft's height above ground. During full power take-off, theaircraft in its ground roll on the surface emits greater noise and itsnoise sphere will be of larger radius than during other phases of itsoperation such as power-off descents to landing. During the power-offlanding approach the aircraft emits much less noise so that its noisesphere will be of smaller radius. When this smaller radius noise sphereduring approach to landing is centered at a height of 40 m above thepavement surface, the cross-sectional area of that smaller noise spherethat actually intersects the plane of the pavement surface will be zeroand, as the descent of a SkyQart proceeds to a height of 20 m or 10 m,the area of said intersection will grow to be more than zero, but willremain less than that of a circle of 40 m radius.

An aircraft's acceptable noise sphere can be better contained within aSkyNest that has a bowl shape (SkyNest IV), because the peak noise oftake-off power is applied at the central bottom of the bowl, whosesloped sidewalls help contain the noise emissions against horizontaldissemination. Similarly, tire chirp noises in a bowl shaped SkyNest IVare contained by the sloped sidewalls of the bowl.

The largest noise sphere for the nominal embodiment of theultra-low-noise SkyQart in this patent is 25.3 m in diameter. This wouldbe the size of the noise sphere at the take-off lift-off location on theSkyNest pavement and represents the noise emissions with a SkyQart I orII with large, slow-turning propellers. Each such propeller emits 35 dBAat full take-off power at a 40 m sideline. The sum of those two 35-dBApropellers' noise would be 38 dBA at the 40 m sideline. The calculationof what would be the radius at which a 38 dBA would measure 48 dBAreveals that radius to be 12.65 m, which is that of a 25.3 m diametercircle. The calculation uses the following formula:

r ₂ =r ₁*10{circumflex over ( )}((dB1−dB2)/20)

This calculation would thus be: r₂=12.65=40×10{circumflex over( )}((38−48)/20)

This means that a 25.3 m diameter noise sphere on take-off is themaximum diameter that fits within the standard SkyNest.

To compare a given noise emission at one distance to what it would be atanother distance, the formula is:

dBr2=dBr1−[20×log 10(r2/r1)]  Equation (3)

where:

r1=the distance from the sound source at which dB r1 exists

r2=the greater distance from the sound source at which dBr2 will exist.An example is as follows: A noise of 48 dB at 40 m, when measured at 80m, by Equation (3), becomes: 48 dB-20×log 10(80/40) 41.98 dB noise at 80m, or roughly 6 dB quieter at twice the sideline distance.

The SkyNest I The SkyNest I is an important component to this invention.For sustainable, high proximity operations, the land parcel size of theSkyNest for QUAD must be minimized while still being large enough tofully confine perceptible aircraft noise to within its boundaries. Usingthe tool of the acceptable noise sphere, the SkyQart's combinedcapabilities of ESTOL and ultra-quiet take-off will be the maindeterminants of the size of the SkyNest. The nominal SkyQart's designperformance in the conflicted goals of ESTOL and low noise emissions areherein pushed to their realistically achievable limits. All versions ofthe SkyQart embodiments presented in this patent conform to thoselimits. This also means that the SkyQart, as a pilotless aircraft, mustbe capable of extreme aerial agility and very precise control of itsflight path and surface operations. The flight path control must include4D positioning. That means not only the three-dimensional (3D) positionof the aircraft but also its 4^(th) dimension of location in time, mustbe sequenced with the other aircraft operations at the SkyNest so as toavoid a conflict or collision. It is important that flight path controlinclude 4D positioning in order to enable the high capacity operationsat each SkyNest. For example, the crossover point between a SkyQart onshort final approach and a SkyQart that is taxiing on a taxiway is apotential conflict unless the separation of the SkyQarts is ensured bystaggered timing.

SkyNest runways will be oriented on their land site in alignment withofficial wind rose data¹⁰.

The SkyNest must also provide enough dock area to process theforeseeable passenger volume at its location. A longer dock can offermore numerous aircraft docking stations for SkyQarts to load/un-load.The different versions of the SkyQart are designed so that theirwingtips can overlap when parked at the dock and thereby achieve tighterspacing between aircraft and greater capacity. The overlap of thewingtips of these versions of the SkyQart enable the longitudinalseparation between aircraft docking stations to be shorter, standardizedat just 4.57 m, a distance that provides sufficient room forhigh-capacity under-dock battery pack processing equipment as well asthe busy top-of-dock bi-directional maneuverings of EPCs and passengers.All SkyNest facilities should share the same nominal interoperabledimension for dock floor height above the pavement, 47.0 cm, along witha nominal interoperable dock width of 7.47 m. Also standardized basedupon the 4.57 m intervals are the locations of the precision positioningsystem. DC fast-charger ports, robotic battery swapping equipment andpin-latch spacings and locations.

There are five basic variations of SkyNest possible depending upon thecost, location, surroundings and passenger volume needed. These fivetypes are:

1. Standard simple SkyNest I, surface sited, high capacity, 1.28 ha

2. SkyNest II, which is a pair of adjacent surface sited, high capacitySkyNest is apposed as mirror images on the sides of a buffer zone andcomprising 2.8 ha

3. SkyNest III, a tiny SkyNest that borders on open space, 0.60 ha

4. SkyNest IV, a circular, bowl-shaped, all winds capable, maximumcapacity SkyNest with sloped surfaces to shorten take-off and landingdistances

5. SkyNest V, a reduced size rooftop circular SkyNest with its dockingat a lower level one-floor down from the rooftop pavement surfaces

Other variations of SkyNest are possible. For example, an initiallow-cost implementation of QUAD service could use SkyNests that have nodock because they simply load and unload on the pavement of existingparking areas at conventional general aviation airports or countryairstrips using the standard autonomous robotic delivery cart (RDC) toload and unload EPCs and battery packs. The use of the standard RDCinstead of dedicated, standardized docking stations would mean muchlonger turnaround cycle times at the shared general aviation SkyNest,which would substantially reduce the capacity of passenger throughput atthose facilities.

The basic standard SkyNest I is a purpose-built design that is surfacesited on a small land parcel with its runway oriented to align with theannual average wind direction at that location. The SkyNest I has simplestandard docking facilities for rapid off-loading of EPCs and batterypacks. A sizeable array of solar panels can be placed above the dock andadjacent streets to provide some portion of the electrical energy use atthe SkyNest I.

The SkyNest II is a larger, surface sited airpark with dual runways thatcan handle more flight operations and thereby larger passengerthroughput. Its runways, taxiways and docking facilities share the samestandard dimensions as those of the standard SkyNest I.

The tiny SkyNest III is sited with more than 50% of its borders on anopen space selected from the group consisting of a shore line, a wildland, a community greenbelt, a highly elevated area around a buildingrooftop and other unpopulated area that is not noise-sensitive. The openspace adjacent to the tiny SkyNest provide areas over which take-off andlanding paths can be directed without annoying people on the ground withnoise or low flying aircraft. This enables the tiny SkyNest to be muchsmaller and less costly and still keep its perceptible aircraft noiseaway from people living near the SkyNest.

The SkyNest IV has a bowl shape with a small flat central area. It canbe surface sited or built into a bowl excavated into the soil. TheSkyNest IV has the highest capacity of any type and is the mostexpensive to build. Its sloped areas are used for downhill take-off runsand uphill landing runs, both of which are oriented into the prevailingwind to further shorten their distances. The design goal of the SkyNestIV remains that of keeping all residential back-yard areas free at alltimes of any aircraft noise level above 48 dBA.

The rooftop SkyNest V can be smaller in area because the noise from itsaircraft operations will be elevated far enough above the street levelas to be non-annoying to people there. This means that, ideally, thelanding surface of the rooftop SkyNest V should be sited at least 36.6 mabove street level in order to minimize its noise impact. For costreasons, the rooftop SkyNest is likely to be built atop existing tallbuildings or multi-level car parking structures. Moreover, for safetyreasons, the rooftop SkyNest V should be placed on the tallest buildingin its general vicinity. In some cases, the rooftop SkyNest V can employsolar panels on its sides to generate a helpful amount of renewableelectrical energy.

The street(s) adjacent to the SkyNest should be walkable, smallresidential or non-arterial streets with speed limits of no more than56.3 km/hr so that they can accommodate pedestrians, bicycles and the40.2 km/hr RDC vehicles from the SkyNest. These streets will alsoprovide bike lanes and some curbside parking spaces for use limited toloading and unloading passengers. Because these streets are not a partof the land parcel that comprises the SkyNest itself, they would bedesigned, built and maintained by the local municipalities. Thesestreets will typically have the following components and dimensions, inthe following order that begins with the portion immediately adjacent tothe SkyNest: A sidewalk that is 2.44 m wide, a bike lane that is 1.83 mwide, short-term (5 minute) parallel parking lane that is 2.44 m wide, acar lane that is 3.05 m wide, a planter/center divide that is 1.83 mwide, a lane 2.44 m wide for an on-demand electric mini-bus, anotherlane 2.44 m wide for an on-demand electric mini-bus that travels in theopposite direction, another planter/center divide that is 1.83 m wide,another car lane that is 3.05 m wide for travel in the oppositedirection of the other car lane, a short-term (5 minute) parallelparking lane that is 2.44 m wide, another bike lane that is 1.83 m wide,and the opposite sidewalk that is 2.44 m wide.

Braking times and distance can be calculated using the braking distanceformula, where “D”, the braking distance is:

D=V²/2×μ×G or meters (m/sec)²/(2×coefficient of friction×9.81 m/sec²),which, for a landing speed of 24 m/sec, equates to 41.9 m for thebraking distance to decelerate to zero km/hr at a continuousdeceleration of 1 G with a 0.7 coefficient of braking friction of thetire on the pavement. However, it should be noted that the landingSkyQart need only decelerate from 24 m/sec to its taxiing speed of 7.6m/sec, so the deceleration distance to zero km/hr can be less than 41.9m or the deceleration rate can be less than one G.

In one embodiment of the QUAD process at an optimum-sized SkyNest I anidealized sequence and turnaround cycle cadence of operations can bedescribed. While this idealized process is generic and can be applied atmany differently sized SkyNests, it represents an extreme case ofexpeditiousness made possible by autonomous operations that allow veryclose aircraft separations and precision positioning of the vehicles.Its rapid cadence provides one departure and one landing every 10seconds. The process described here is one of maximum performance in afully implemented, autonomous high-capacity QUAD transportation system.This extreme case of the process with its rapid cadence serves to definethe potential limits for speeds, distances and sizes that can be used todevelop standards for the smallest conceivable SkyNests in a fullyautonomous, optimized QUAD system. This process and its cadence areherein named the cadenced coordinated operations at SkyNests. If alldepartures are fully loaded, 6-seat SkyQart III's, then 6×6=36 peopleper minute can be launched. For the 1.28 ha SkyNest I, this calculatesto it having a potential maximum capacity of launching 683 people peracre per hour and launching 2160 people per hour. Note that both thestandard SkyNest and the other variants of it rely upon operationalsequences that demand safe movements of aircraft at very close proximityto one another. Such close separations are unprecedented and will likelyrequire special FAA regulations to permit them. That permission willdepend upon QUAD having the ultra-quiet SkyQarts whose autonomous,precision positioning system using on-board navigation systems, senseand avoid systems and wheelmotor controllers operate with impeccablesafety and to certificated standards. This invention thus includes suchcapable SkyQarts in its process. The reason for the “Q” in QUAD is that‘quiet’ is the most distinguishing feature of the system. The acceptablenoise sphere tool is thus valuable to ensuring that all SkyNest designswill be community acceptable. Keeping SkyNests as small as possible iswhat enables them to be close to where people live and work, and thisenables them to reach a mass-market and provide meaningful benefits tothe public transportation system. However, the smaller the SkyNest, thegreater the likelihood that the noise of its aircraft will adverselyimpact the SkyNest neighbors.

The nominal embodiment of the SkyNest I has an area of 1.28 ha. This isthe smallest size that can be located inside a quiet residential areaand still confine the SkyNest noise to within SkyNest boundaries.Smaller SkyNests III can be used in other settings. For example, if atleast 50% of its perimeter borders on open space, the SkyNest III can beas small as 0.6 ha and still provide the required noise containment.QUAD SkyNests located within urban and industrial areas where highlevels of ambient noise exist, and those with fewer flight operationsthat are located within large, privately-owned campuses, ranches orfamily compounds, can also be smaller than the 1.28 ha SkyNest Iembodiment presented in this patent, but each must still providecommunity-acceptable noise containment at the public margins of thoseproperties. SkyNests larger than 1.28 ha can have similar operationalcadences to those described herein, but there must be a match betweenthe size of the SkyNest land parcel, the speeds and landing distances ofthe SkyQarts operating there, and the climb-out and landing approachtrajectories and distances necessary to ensure that the potentiallyannoying noise emissions of the aircraft, according to an acceptablenoise sphere, are confined within the SkyNest boundaries or kept awayfrom noise-sensitive developed areas. It will be possible to ‘carve out’various sizes of SkyNests within existing larger conventional take-offand landing airports in order to create early implementations of theQUAD process. By these requirements then, for practical purposes, thisinvention of the QUAD process is limited to SkyNests of sizes rangingfrom 0.4-5.0 ha.

In the operations at a SkyNest I presented herein, the aircraft that areairborne within the SkyNest boundaries are operating at 24 m/sec andthose that are on the SkyNest surface are moving at 7.6 m/sec. These arethe nominal interoperable speeds that tailor the distances that can besafely and expeditiously covered in each 10-second operational step inthe sequence of landing, taxiing to the loading dock, taxiing to thedeparture runway and taking off again, to the actual size of the SkyNestland parcel. High capacity autonomous QUAD operations will ultimatelyrequire such scripted and extremely rapid cadences of operations inorder to be affordable, efficient, and of meaningful volume. There is noprovision in this extreme example of cadenced coordinated operations atSkyNests for delays in aircraft movement, such as would occur with thesustained hovering required by vertical take-off and landing (VTOL)aircraft, or by indecisive, hesitant human pilots, although these delaysmay occur in early implementations of the QUAD system.

The ideal fast cadences for loading and unloading of payloads on theSkyNest's dock are likewise modeled for very rapid turnaround times andrely on robotic equipment and pre-loaded EPCs. While these stepsrepresent the ideal, fully developed system with maximum capacity forthe SkyNest, this system invention nevertheless includes the slower,manual, less developed operational cadences that occur during the earlydevelopment and evolution of the QUAD system.

A nominal SkyNest I whose dimensions are 167.6 m×76.2 m, amounts to 1.28ha of land. The steps in the operational sequence of the SkyQarts atthis SkyNest are modeled to consume 10 seconds each, including 10seconds for de-boarding and 10 seconds for boarding. This rapid cadenceof operations is predicated on fully autonomous aircraft operating in afully developed QUAD system process and is designed to maximizepassenger throughput. This process and its cadence comprise the cadencedcoordinated operations at SkyNests.

The following description of the steps by which a SkyQart aircraft canapproach, land, taxi to the dock, park, deboard, board, refresh its SBP,taxi for departure, take-off and climb out of a SkyNest I will presentthe typical turnaround cycle at a busy SkyNest. The SkyQart, during itslanding approach, enters the SkyNest boundary at a prescribed height andlocation that depend upon the current wind direction. For noiseabatement purposes, it descends steeply from that location with aroughly 30° bank angle, and with its propellers producing drag bywind-milling in electricity regeneration mode, it descends from aninitial height above ground level of roughly 30 m. At this initialheight, its power-off noise emissions are so low as to be nearlyimperceptible on the ground. The SkyQart proceeds to descend along acurved flight path toward the landing area of the SkyNest pavement. Thiscurved traffic pattern is deliberate because it provides the SkyQartwith a longer distance over which to complete its descent over theSkyNest property. The curved traffic pattern can be a precise, 4D, steepand banked curvilinear landing approach or climb out profile and is animportant component for enabling SkyNests to as small as possible.

Descending at an airspeed of 24 m/sec, the SkyQart travels in 5.6seconds a curved traffic pattern of 106.4 m as its landing approach pathreaches the point of landing touch-down on the SkyNest. The SkyQart thenconsumes another 4.4 seconds by rapidly decelerating to the 7.6 m/sectaxiing speed at which speed it turns to begin its taxiing to the dock.Its approach, landing roll and turn off consume just 10 seconds afterentering the SkyNest boundary. The SkyQart then continues taxiing at thespeed of 7.6 m/sec to seamlessly reach a position along the arrivaltaxiway which is close by to an empty aircraft docking station at thedock. The SkyQart then stops taxiing and proceeds to use its wheelmotorsto precisely back into the empty aircraft docking station, which itaccomplishes in 10 seconds using its multi-sensor guided precisionpositioning system. The backing in and parking process rely onelectronic vehicle guidance using the SkyQart's wheelmotors along withthe active main landing gear ride height adjustment to consistentlyachieve a precise docking alignment to within ±2.0 mm.

The precision positioning system (PPS) is an important innovation inthis invention. It is an on-board system that enables the SkyQart, theEPC and the RDC to precisely dock. The PPS enables the SkyQart to berapidly parked in exactly the aligned position at the aircraft dockingstation such that it can rapidly load and unload both SBPs and EPCs.This is accomplished using a PPS comprised of one or more of thefollowing guidance technologies: differential GPS, inertial navigationsystem (INS), line-following software, obstacle-avoiding video camera(s)vision system, auto-focus technologies of either active infrared or avertical and horizontal auto-focusing charge-coupled device (CCD) camerachip, a 4-beam convergent bio-medical He—Ne laser targeting atransponding receiver plate on the dock, and a capacitive proximitysensor for the final alignment to the dock surface. The line-followingsoftware on the SkyQart can accurately follow a curved guidelineemanating outward on the pavement from the edge of each aircraft dockingstation. This curved guideline for the SkyQart is continuous frombeneath the edge of the centerpoint of the aircraft docking station andit emanates outward from there onto the SkyNest parking ramp. Thiscurved guideline has a fixed width in the range of 3.175 mm to 12.7 mmwith sharp edges. This line is either painted, taped on or projected bylaser, and is of a color that sharply contrasts with that of thepavement. This line provides an alignment path to guide theline-following software that is on-board the SkyQart that intends tomove precisely to the center of that aircraft docking station.

This combined parking alignment technology is important and consistentlyaligns the parked SkyQart to within nominally ±2.0 mm of the center ofthe aircraft docking station so as to enable rapid loading and unloadingof EPCs, as well as automated connection of the SkyQart to the dock's DCfast-charging port. Two slightly tapered solenoid-actuated pins in thedock are spaced a nominal 81.28 cm apart and are engaged into the twopin alignment holes in the aft face of the SkyQart's floorboard, whichare likewise 81.28 cm apart. The engagement of these pins helps maintainthe necessary alignment of the SkyQart to the dock. Automated heightadjustment of the active main landing gear of the SkyQart can also helpmaintain correct alignment during docking.

Just prior to backing-in to its allotted aircraft docking station, theSkyQart automatically opens its rear loading hatch door to prepare forcharging and/or unloading/loading of its EPC at the dock. Unloading ofthe EPC from the SkyQart will be followed immediately by the reloadingof a laden EPC waiting on the dock for that particular SkyQart. Thisreloading of an EPC into a SkyQart is facilitated by the EPC having itsown on-board navigation and autonomous control system along with a PPSwith line-following software that can accurately follow a curvedguideline emanating outward onto the dock surface from the dock edge atthe center of each docking station. This curved guideline for the EPC onthe dock surface is continuous, originating at the centerpoint of thedocking station and emanating outward onto the dock surface from there.This curved guideline has a fixed width in the range of 3.175 mm to 12.7mm and has sharp edges. This curved guideline is either painted, tapedon or projected by laser, and is of a color that sharply contrasts withthat of the dock surface. This guideline provides an alignment path toguide the line-following software that is on-board the EPC that intendsto move precisely to the said center of that docking station. Unloadingand reloading are each ideally accomplished in just 10 seconds, eachusing the nominal interoperable embodiment of the EPC that is 144.8 cmL×103.2 cm W.

Concurrent with these 20 seconds that the SkyQart spends at the dock, arobot located at the aircraft docking station can remove the SkyQart'sspent standard swappable battery pack (SBP) and insert a freshly chargedone into drawer slide rollers that guide it precisely into the belly ofthe SkyQart, where its correct position, latching and electricalintegrity are automatically confirmed. Battery pack replacement need notoccur at every instance of docking, depending upon the particular rangeof trips being flown by that SkyQart and the total range available perbattery pack. As future battery energy densities and charging ratesimprove and the average distance of QUAD flights diminishes, thefrequency with which these robotic battery pack swaps occur at the dockwill diminish and, for some applications, automated DC fast-charginginstead of battery swap will occur from the dock's DC fast-charging portwhile the SkyQart is docked for a few minutes. Such automatedfast-charging is also more likely in cases where a SkyQart's energystorage is by super-capacitor.

Just 20 seconds after arriving at the dock, when the SkyQart hascompleted its unloading and reloading with concurrent replacement of itsSBP, it then departs the dock, and proceeds in 10 seconds to taxi ontothe taxiway that is adjacent to the pavement for take-off and landing,heading toward the take-off area. The SkyQart then continues its taxiingfor another 10 seconds to reach that take-off area where it stops towait in place for take-off. Next, the SkyQart taxis in less than 10seconds into the take-off position for brake release on take-off. Uponbrake release, the nominal interoperable SkyQart rapidly accelerates in4.66 seconds to roll 43.9 m on wet pavement in no wind conditions, whileundergoing no more than 0.69 G's of acceleration, to reach lift-off. Itsacceleration is conducted with guided rate acceleration change execution(GRACE) with a jerk rate that is kept below 3.4 m/sec³ at all pointsduring the take-off. From its lift-off position, the SkyQart climbssteeply on a curved traffic pattern over a ground surface distance of104.5 m in 4.66 seconds at an indicated airspeed of 24 m/sec to reach injust under 10 seconds a height of 40 m above ground level (AGL) at aposition near the boundary of the SkyNest. At this position, the noiseof the departing SkyQart is nearly imperceptible on the ground. Thetiming of the take-off is maximally staggered with that of the landingaircraft so that a safe 4D separation is always maintained between thetwo curved traffic patterns of the arriving and departing SkyQarts. Thesteep descent and climb gradients ensure that the flight paths over thetaxiways are well above the height of any taxiing SkyQart.

The total turnaround time consumed by the SkyQart is 100 seconds, asdescribed in the above example of moving through the sequence ofpositions, and that 100 seconds is comprised of the following steps inthe turnaround cycle:

10 seconds for descent, landing and turning off of the landing pavement

10 seconds for the first leg of taxiing

10 seconds for second leg of taxiing

10 seconds for precisely backing into the aircraft docking station

20 seconds parked at the dock: 10 seconds to de-board and 10 seconds toboard

concurrent battery swapping during the 20 seconds parked at the dock

10 seconds for the first leg of taxiing for departure

10 seconds for the second leg of taxiing for departure

10 seconds for taxiing onto the take-off brake release point

10 seconds for take-off and climb-out to the SkyNest boundary

Total: 100 seconds turnaround time (TAT).

At maximum, with departures every 10 seconds by a SkyQart seating 3passengers, a SkyNest I with a single runway can move 18 passengers perminute or 1080 passengers per hour. However, this assumes a very close4D intermingling of landing and departing traffic.

The Cart Service building includes EPC and RDC cleaning, inspection,testing, preparation, modification, battery swapping and otherservicing.

The Cargo Service building is where cargo containers may be loaded,unloaded, cleaned, inspected, attached to or removed from empty EPCs. Inthis building, there may be customer will-call pick-up and drop-off ofdeparting or arriving packages as well as loading of packages from andonto various types of road vehicles for last mile delivery. Futurespecialized autonomous EPCs with cargo hauling attachments will becapable of exiting a SkyQart onto the dock, pin-latching in piggybackfashion onto the surface deck of a waiting RDC, and then leaving theSkyNest's dock as the RDC with EPC aboard drives onto neighborhoodstreets to robotically complete the last mile home delivery of shippedparcels. After such delivery, the RDC returns autonomously (‘deadhead’)to the SkyNest dock where it would unload its EPC and become ready forfurther delivery service. Such autonomous last mile RDCs can qualify asneighborhood electric vehicles that carry passengers or cargo onresidential streets. The RDC is designed to fit the basic size, weight,height and EPC attachment standards given in this patent so as to beinteroperable with QUAD and with trucking dock standards. The details ofsize and attachment standards for such an embodiment of the RDC areincluded in this invention. Also available at the SkyNest will beancillary businesses such as restaurants, shipping companies,coffee-houses, mini-marts, car, cart and bike rental, taxicab and busparking, bicycle rack, etc.

The SkyNest I can have a renewable energy source on site. It can have anominally 167.6 m×48.8 m solar panel array that covers both its dockarea and the adjacent street, comprising a nominal area of 8175 sq m.With the best commercially available solar panels of 2020, this largesolar panel array would produce a maximum of 1,800 kilowatts of power onsite. The maximum power produced by this large array at the SkyNest Icould then theoretically provide a maximum of 100 kilowatts of chargingpower for each of eighteen SkyQart standard battery packs (SBP). Thiscapacity could double if the energy capture of future commerciallyavailable solar panels were to double.

At minimum, a nominal SkyNest must provide a 67 m length of pavement forlanding, with nominally 30.2 m of that consumed during landing gearsquish and an overlapping 39.2 m needed in order to decelerate on drypavement from 24 m/sec to 7.6 m/sec at −0.7G. In regions subject toicing conditions, this length of pavement and other portions of theSkyNest surface may be heated. There will be, at minimum, 43.9 mnecessary to decelerate from 24 m/sec to 7.6 m/sec at −0.6G if on wet,flat pavement. A nominal descent within GRACE consumes a 24.4 mhorizontal distance to initial touchdown from a height of 3 meters aboveground level, which is a minimum ‘over the fence’ height for landing ata SkyNest.

The distance over the ground (surface) that is consumed in a steep,curved final landing approach to touch-down from a height of 30 metersin a 30° bank and at an initial sink rate of 30 fps is 106.4 m if thedescent and touch-down are limited to a jerk rate of 3.4 m/sec³ and thetouch-down occurs at a sink rate reduced to 0.% m/sec, a rate that canbe manageably dissipated by the SkyQart's active main landing gearmechanism. The same path and touch-down from a height of 40 metersconsumes a nominal 130.8 m.

The SkyNest II

The nominal SkyNest II is an important component to this invention. Ithas an area of 2.8 ha, and is a higher capacity SkyNest at which two ofthe 1.28 ha SkyNest I facilities are sited as mirror-images. A requiredminimum buffer zone that is 12.2 m W×167.6 m L is placed between the twoSkyNest I facilities to create the SkyNest II in order to ensureadequate separation of the aircraft that operate concurrently on itsparallel runways. The nominal 12.2 m width of this minimum buffer zonepresumes that the autonomously operating SkyQarts will have sufficientprecision in controlling their flight path to maintain safe lateralseparations when landing or taking off simultaneously on the two runwaysof the SkyNest II, even during gusting and cross-wind conditions. If alldepartures were made by fully loaded 6-seat SkyQart IIIs at a rate ofsix departures per minute per runway at the SkyNest II, then 36 peopleper minute per runway could be launched and this would equate to ithaving a potential maximum capacity of launching 632 people per acre perhour and 4320 people launched per hour. If two SkyQarts of variant I orII, each with a 10.97 m wingspan, were landing or taking offsimultaneously and were moving along the centerline of their respectiverunways, the 12.2 m wide minimum buffer zone would provide for a nominalseparation of 25.7 m for their respective wingtips. In the unlikelyevent that two SkyQarts III were so operating, their larger wingspanwould cause their wingtip separation to be 16.95 m. The area of the 12.2m×167.6 m minimum buffer zone, when added to the 1.28 ha of each of theSkyNest I's yields a SkyNest II that occupies a total of 2.8 ha of levelland. This nominal size of SkyNest II can provide twice the passengerthroughput capacity of the SkyNest I. The 4D flight operations above thetaxiways of the SkyNest II are calculated to maintain adequate verticalseparation of the taxiing aircraft from those that are taking off andlanding. The SkyNest II is shown with two large but separate solar panelarrays, each one covering both the dock area and the adjacent streetwith nominal dimensions of 167.6 m×48.8 m, making 8175.5 sq m. With thebest commercially available solar panels of 2020, each large solar panelarray of this size could produce a maximum of 1800 kilowatts of power inthose conditions. The combined maximum energy of two such large arraysat the SkyNest II would then be 3600 kilowatts, which couldtheoretically provide a maximum of 100 kilowatts of charging power foreach of 36 SkyQart standard battery packs. This 3600 kilowatts of powercould double to 7200 kilowatts with a future doubling of solar panelefficiency.

The SkyNest III

The SkyNest III is an important component to this invention. It is aminimum sized, reduced capacity SkyNest that can be sited on theperiphery of noise-sensitive developed residential or commercial areaswhen those areas are bounded by open space such as bodies of water orgreenbelts. Instead of confining the acceptable noise sphere to withinthe SkyNest boundaries, the tiny SkyNest III relies upon the reducednoise sensitivity of the adjacent open space that is a body of water orgreenbelt as a flyover zone for low-flying SkyQarts that are taking offor landing. In effect, the SkyNest III allows its acceptable noisesphere to overlap with that open space in order to allow the SkyNest IIIto be smaller in size. Its nominal land parcel size is 99.1 m×61.0 m andthis comprises 0.6 ha instead of the 1.28 ha of the nominal SkyNest I.This smaller size is a minimum for the safe take-off and landings ofSkyQarts whose lift-off and touchdown airspeeds are 24 m/sec. TheSkyNest III could be alternatively sited fully inside a developed areaas a single-level rooftop facility, if said rooftop is of sufficientarea and is sufficiently high above street level. The take-off noise ofdeparting SkyQarts must at all times keep the acceptable noise spherewithin the airpark's fence or boundary with the noise-sensitive adjacentdeveloped community. This requirement is met by having the center of therunway of the SkyNest III a distance of greater than 40 meters from thesidewalk boundary of that facility.

The crash cushion used at the SkyNest III can be either fixed inposition at each end of the runway, movable as a unit to be positionedat the far end of the active runway, or the more expensive option ofbeing a crash cushion that is retractable into the ground to enhanceground clearance for landing SkyQarts. The stairs that lead up fromstreet level to the dock at the SkyNest III are consistent with thestandards used at the SkyNests I, II, IV and V, in having a nominal 15.7cm rise with a 35.6 cm tread and are 1.83 m wide.

The SkyNest IV (a Bowl-Shaped Airport)

The SkyNest IV is an important component to this invention. It is thelargest and highest capacity SkyNest facility intended for siting neartransportation hubs that require high passenger throughput and sustainedoperation regardless of wind direction. Built in its largest embodiment,that being as an above-ground structure like a stadium, it occupies aland parcel size of nominally 192.6 m×213.7 m, comprising 4.12 ha. Alsolike a stadium, it has a circular bowl shape with sloping pavements thatensure extremely short take-off and landing distances for the SkyQartsthat operate there. The bowl-shaped SkyNest IV can built above-ground orcan be excavated into an area below ground level, depending upon thelocal terrain, soil and ground water table conditions, with theabove-ground version being more expensive to build. On sloped terrain, ahybrid of the above-ground and excavated types can be built, as in theembodiment presented in this patent. Depending upon its size and numberof vehicle lanes, the street design affects the area impacted by theoperational aircraft noise at any SkyNest. The design of the streetinterface with the dock facilities used at the SkyNest IV can be of twotypes and the type chosen will depend upon whether it is theabove-ground version or the excavated version. Both types of streetdesign can be used for a hybrid SkyNest IV. The particular design usedcan be altered to be any of several variants and still be encompassed bythis patent. The above-ground SkyNest IV provides access for RDCs fromstreet level to reach its upper level dock(s) by providing down-rampsand/or elevators designed for that purpose. Passenger elevators mustalso be provided, along with stairways. The size, shape, number andlocation of the access ramps, elevators and stairways from street levelat a SkyNest IV may differ from those shown in this embodiment and suchalternative variations are also included in this patent. Theabove-ground SkyNest IV must provide at its truck dock/cargo servicearea at least one large freight elevator capable of carrying a mid-sizepickup truck from street level up to dock level. The size, shape, numberand location of freight elevator(s) may differ from that shown in thisembodiment and such alternative embodiments are also included in thispatent. The above-ground SkyNest IV, if equipped with a dock on each oftwo sides that each include one aircraft docking station for the largerSkyQart III, can provide thirteen SkyQart docking spaces along eachside, making 26 docking spaces in all. The hybrid SkyNest IV, ifequipped with one dock on its ground-level side and another on itsabove-ground opposite side, can provide sixteen docking spaces on theground-level side and thirteen docking spaces on the above-ground side,making 29 docking spaces in all, again including one aircraft dockingstation on each dock side for the larger SkyQart III. The excavated bowltype of SkyNest IV with street-level docks on two opposite sides canprovide sixteen aircraft docking stations per dock side making 32docking spaces in all, again including aircraft docking station on eachdock side for the larger SkyQart III. The ideal and standard slope forthe SkyNest IV pavement is 10%, wherein a 6.4 m vertical drop occursacross 64 m of horizontal distance. This equates to an angle of 5.71°and, according to the cosine of 5.71°, provides a sloped pavement lengthof 64.3 m across 64 m of horizontal distance. The 64.3 m of slopedpavement length, along with the 15.24 m diameter flat circle of pavementconcentric with the center of the circular bowl, provide a pavement pathlong enough for safe liftoffs and touchdowns of the 24 m/sec airspeed ofthe SkyQart. This 10% slope is ideal because a less steep pavement slopeoffers insufficient advantages while a steeper slope becomes untenabledue to take-off and landing trajectories having insufficient groundclearance along with problems in using a steeper slope forcircumferential taxiing. The 10% slope used in this embodiment requiresuse of steep, precisely-scripted climb and approach trajectories usingcurved traffic patterns in order to avoid traffic conflicts and fulfillGRACE requirements. In the unlikely event of having a SkyQart on itssteep landing approach in a no-wind condition overfly a SkyQart that istaxiing circumferentially along the sloped upper portion of the bowl,the steep landing approach will still provide 4.15 m of clearance abovethe top of the T-tail of the taxiing SkyQart. Landing with any windabove zero would increase that 4.15 m clearance. These steeptrajectories are selected to fit the aerial agility, negligible controllatency, drag augmentation and climb capabilities of the SkyQarts and inall cases in this embodiment are calculated to comply with the GRACErequirements. Both the standard, no-wind landing trajectory and that fora 16.1 km/hr headwind velocity can be safely conducted at the SkyNestIV. These landing trajectories are both constrained to use the sameideal or target touchdown point, which is 3.8 m beyond the center of thebowl. That is a location that ensures adequate ground clearance allalong the path of a no-wind (most-constraining) landing approach. Alllanding trajectories at a SkyNest IV use a curved traffic pattern in aleft turn until they become fully aligned with the landing runwayheading just before reaching the center of the bowl. The curved trafficpatterns of the curved climb-out trajectories do not begin at theliftoff point on the pavement, which liftoff point will vary accordingto the wind velocity at the time. Instead, before initiating any headingchange, all climb-outs begin by continuing straight and level flight tofly at very low altitude over the center of the bowl while maintainingthe heading used during the initial take-off distance. All landingtrajectories likewise proceed to fly at low altitude over the center ofthe bowl. The center of the bowl is thus an intersection at whichSkyQarts that are landing and taking off have a potential trafficconflict. That conflict can be averted using the networked situationalawareness and autonomous control system to maintain all traffic on timed4D trajectories that do not intersect. The divergence of the landing andclimb-out flight paths at all other points approaching and beyond thissingular intersection at the center of the bowl helps to ensure the safeseparations for the SkyQarts operating at the SkyNest IV. A nominal 19.8m wide level perimeter deck surrounds the upper rim of the bowl andoffers, in conjunction with the uppermost portion of the sloped bowlsurfaces, ample space for SkyQarts to bi-directionally taxi and maneuverinto and out of the dock area. The dock area is of the standard sizeused at all other types of SkyNests, being 7.5 m wide and 47 cm tall.The significant benefits from using ideally sloped runways are asfollows:

less power and noise needed for take-off (saves weight in wheelmotors)

less take-off distance required

reduced tendency for wheelies on take-off

less landing ground roll required, even with wet pavement

greater safety in event of brake failure

always landing and taking off into whatever wind is present

affordable infrastructure with leasable surrounding commercial buildinguse

capable of saving water runoff to a central drain

surpassing a SkyNest II in passenger capacity per acre

noise reduction at the noisiest portion of the SkyNest (the liftoffarea)

All SkyNests may use on their paved surfaces a heated, poro-elastic roadsurface (PERS) or other variant from asphalt or concrete as a helpfulmethod to reduce tire noise and enhance wet traction, as described by L.Goubert, Belgian Road Research Centre, Belgium¹¹

If built on top of the local land surface rather than as an excavatedbowl, a perimeter tall enough for convenient, compatible street levelcommercial businesses and low-cost housing can allow the co-location ofthese within the land parcel size of the SkyNest IV. These may includeapartments as well as businesses such as shipping, restaurants, smallgrocery, etc. The effect of having such useful and leasable propertiesembedded around all sides of an above-ground SkyNest TV effectivelyreduces the size of the land parcel actually dedicated for its surfaceand flight operations (and excluding its dock areas) to just 143.3m×143.3 m or 2.05 ha. These mixed uses of the buildings underneath theabove-ground SkyNest IV increase the walkability, utility,attractiveness and property values of the neighborhood around theSkyNest IV.

The portion of acceleration due to gravity, “G” that acts constantlyalong the downhill slope at a SkyNest IV is GSinθ, if θ is the includedslope angle. If the angle is that of a 6.4 m rise that occurs across a64 m run, then the angle will be ATAN(21/210) or ATAN(0.1). That angleis therefore 5.711° and its sine is 0.1, which means that 0.1 G areacting continuously along the downhill (hypotenuse) slope of the ramp toassist in take-off acceleration, or, when the SkyQart is landing uphill,acting continuously as a constant braking deceleration assist¹². The 10%slope provides these 0.1 G acceleration and deceleration assists totake-offs and landings regardless of the wind level or whether thepavement is wet or dry. The 10% slope provides enough decelerationassist that, in a worst-case scenario, a SkyQart can decelerate from itstouchdown speed of 24 m/sec to the 7.6 m/sec taxiing speed when landinguphill in only 37.8 m with no headwind and no reverse thrust, if a 16.1km/hr headwind is present and reverse propeller thrust is used, thisdeceleration distance can be reduced by more than 15.24 m.

The SkyNest IV reduces noise by reducing take-off power required, by itsbowl shape serving as a sound wall, by placing the loudest part oftire/pavement noise into the center of the bowl (same for touch-downtire chirp). It also will slow down an abortive take-off with its uphillramp, ensure consistency with into-the-wind take-offs and landings byoffering any runway direction, varying the climb-out trajectory so thatit is not always over the same neighbor's house, quell wind velocitiesdown inside the bowl, reduce tire wear, capture water forirrigation/industrial use, potentially use some of its bowl surfaces asa solar panel array, use the perimeter outside the above-ground bowl toprovide 1^(st) floor and 2^(nd) floor areas for small businessesunderneath the dock areas, and use the bowl surfaces for taxiing and/ornight-time parking of SkyQarts after curfew. In an alternativeembodiment, the SkyNest IV could expand its dock area to encompass itsentire perimeter and extend SkyNest pedestrian entries to all sides ofthe block perimeter. The dock can be protected with movable QUAD crashcushion carts that are placed at the terminus of each active runway. TheSkyNest IV increases fixed initial infrastructure cost but can reclaimthat cost by leasing its attractively located street level propertiesand in fees for its high capacity operations. The SkyNest IV offers thepossibility of as many as six departures per minute, one every 10seconds, interspersed with six landings in that same minute. If all sixdepartures were for SkyQart III aircraft with six people aboard eachaircraft, that would launch a maximum of (6×6×60)=2160 people per hourper above-ground SkyNest IV as an extreme of capacity.

Fillets in the paved surfaces at both the top and bottom of the bowlramps smooth the transition across them. Rather than earth-fill, theabove-ground-level, bowl-shaped SkyNest IV can be built like astadium³³, on steel truss or concrete underpinnings for stability andaccuracy in its geometric shapes. The steel and concrete constructionmethod that is used in multi-level carparks can be employed for theabove-ground bowl shape.

With the sloped runways at the SkyNest IV, the distance to deceleratefrom a touch-down speed of 24 m/sec to taxiing/turnoff speed of 7.6m/sec is only 37.7 m if the landing is uphill with no wind and noreverse propeller thrust is employed.

The trajectories of both climb-out and landing at the SkyNest IV must beprecisely conducted in order to ensure ideal use of the advantagedacceleration or deceleration imparted by the sloped runways at theSkyNest IV. Such precision trajectories are made possible by autonomousflight controls with negligible control latency. The circle of levelfloor at the center of the bowl shape of the SkyNest IV has a nominaldiameter of 15.24 m. To ensure clearance of the downhill sloped pavementduring final approach, a SkyQart landing with a correct trajectory mustcontinue flying until it is directly over the center of this circle andmust then touch-down at a point that is 3.81 m beyond the center of thiscircle.

In order to gain sufficient height when climbing to clear the oppositeup-sloped portion of the bowl, the climb-out trajectory of the departingSkyQart must begin with a liftoff that occurs at or before a ground rolldistance of 42.7 m from the point of its brake release at the top edgeof the bowl. This performance demands the use of a combination oflanding gear wheelmotors and propeller thrust to achieve a brisk rate oftake-off acceleration that is still compliant with GRACE requirements.

The SkyNest TV will have separate runways for take-off and landing, withtheir respective runway headings 30° apart in order to enhance theseparation of the aircraft that are landing from those that are takingoff. The heading of these runways will change according to the winddirection, as follows: Each of the two runway headings will be orientedon either side of the prevailing wind heading, making each runwayheading nominally 15° different from the present wind direction. Forexample, if the wind heading is from 30°, then the headings of the tworunways will be 15° and 45°, making them 30° apart but causing themaximum crosswind angle to be only 15° for either of these runways. Thisalignment would cause the maximum crosswind component to be consistentlylimited to just 25% of the prevailing windspeed, thus allowing take-offs and landings in windspeeds as high as 96.6 km/hr with only a 24.1km/hr crosswind component. If the runway headings were, instead of 30°apart, only 20° apart, the likelihood of traffic conflict would increasewithout significant gain in crosswind protection. Likewise, if therunway headings were 45° apart, the gain in reducing traffic conflictwould not be significant relative to the worsening of the crosswindprotection. Therefore, runway headings that are 30° apart are thestandard for the SkyNest IV.

At the perimeter of the sloped sides of the bowl at the SkyNest IV,there is a nominal 19.8 m wide, level peripheral taxiway for SkyQarts touse, in addition to which, when traffic allows, SkyQarts can use thesloped walls of the upper portion of the bowl at the SkyNest IV as ataxiway.

The dock at the SkyNest IV has the same standardized dimensions as thatat the SkyNests I, II and III, being 7.5 m wide and 47 cm tall.

After take-off, climbing to a 40 m height above ground is normallyrequired of all SkyQarts to achieve community-acceptable noise levels atthe outer boundaries of the SkyNests I, II, III and IV. The climb-out ofthe SkyQart normally requires a distance of 129.2 m in order to reachthis 40 m height, when such climb-out is conducted over level ground incompliance with GRACE requirements. When this climb-out arc is conductedfrom a downhill pavement toward the opposite uphill pavement at aSkyNest IV, the ground clearances at all locations along the initialclimb-out trajectory are reduced due to the SkyQart's liftoff occurringin a 5.71° downhill trajectory. The height above ground achieved at agiven distance from the take-off brake release at a SkyNest IV will thusbe less than that at a SkyNest I, II or III due to the initial downhilltrajectory of the SkyQart at the SkyNest IV. The ground clearances arealso affected by the location on the runway at which liftoff occurs,which, in turn, depends upon the wind velocity. After brake release atthe top rim of the bowl of the SkyNest in a no wind condition, the pointof lift off must occur within a worst-case ground roll distance of nomore than 42.7 m in order to ensure sufficient ground clearance at alllocations along the climb-out trajectory at a SkyNest IV. Immediately atthe moment of liftoff in a standard take-off trajectory, the SkyQartwill execute a climb in which it maintains its initial heading until itreaches the center of the bowl. In the no wind condition, the planardistance from liftoff to the center of the bowl is 29.0 m. From thecenter of the bowl, the departing SkyQart then continues its climb byexecuting a left turn in a 30° bank angle to climb a horizontal distanceof 100.3 m along a curved traffic pattern to reach a height above groundof 40 m. At the SkyNest IV, the combination of the beneficial effects ofa downhill pavement and taking off always into the wind can help toshorten the take-off distance and can make the nominal 42.7 m groundroll distance readily and consistently achievable by the SkyQarts I, IIand III. For example, if the effective wind velocity on the runwaysurface is 17.1 km/hr, then the nominal 42.7 m take-off distance wouldinstead be shortened to just 27.1 m, even when performed with therequisite GRACE. Likewise, a direct headwind velocity of 34.2 km/hrwould reduce the take-off distance to just 16.8 m with GRACE. Suchshortened ground rolls will cause the SkyQart to begin its climb-out ata position that is higher above the bottom of the bowl and thus affordsubstantially greater ground clearance throughout the climb-outtrajectory. When the climb-out is initiated in a no wind condition at aliftoff that is exactly 42.7 m from the edge of the top of the bowl andis correctly conducted at an airspeed of 24 m/sec, then the climbingSkyQart will achieve a sufficient clearance height above all locationsalong the bottom and opposite (uphill) side of the SkyNest IV. Formaximizing ground clearance after lift-off, the path projected over theground of the climb-out trajectory must continue straight along theinitial heading until it reaches the center of the SkyNest TV bowl, atwhich position the curved 30° banking climb trajectory must consistentlyand immediately begin.

Each SkyNest IV will have a small portion of its periphery devoted to asmall aircraft hangar to enable any necessary maintenance, repair oroverhaul (MRO) to the vehicles that operate there.

The perimeter of the top of the bowl at the SkyNest IV is 19.8 m fromthe closest dock edge, in order to provide adequate room forbi-directional taxiing of SkyQarts I, II and III.

The SkyNest IV bowl shape must have a nominal 7.6 m radius flat,non-sloped central circular area to serve as a transition from one sideof the bowl to the other.

The SkyNest IV bowl has a planar (top view) radius of nominally 71.6 mincluding the flat, non-sloped central circular area of 7.6 m radiusthat is concentric to the center of the bowl.

The SkyNest IV can be configured with dock facilities on one, two, threeor four, of its outer sides.

The bordering streets along one or more of sides of the SkyNest IV canbe any of several types. Ideally, such streets would include bike lanes,short term parking, bus stop areas, loading zones, and a centralbi-directional pair of lanes for electric mini-bus transit service.

The SkyNest IV standards for the pavement slopes, bowl size, taxiwaysand dock area dimensions are the minimums that can provide the necessarylow-noise, steep landings and take-off s for the SkyQarts I, II and III.The SkyNest IV dock area can accommodate as many as sixteen SkyQarts perside dock if only one of those sixteen aircraft is the six-seat SkyQartIII with its larger wingspan.

The Rooftop SkyNest V

The SkyNest V is an important component to this invention. It ispossible to place a SkyNest atop a tall building or multi-level parkingstructure. The configuration of such rooftop SkyNests will depend uponthe height of its building, the planar size of its rooftop and theheight and proximity of adjacent tall buildings or trees. The mainpurpose of a rooftop SkyNest is to provide acceptably quiet, highproximity access to QUAD service in highly developed, surface-congestedareas such as metro centers, urban canyons or major hub airportterminals. In some cases, a SkyNest can be added to the roof of anexisting building or structure while in other cases it will be appliedto a purpose-built building. It may be applied to the roof of existingparking garages at major hub airports. In all cases, there must beunobstructed approaches and departure paths to the pavement of a rooftopSkyNest, and the size of its pavement and docks must match theperformance capabilities and dimensions of the SkyQarts describedherein, just as is true for the each of the standard sizes embodied inthe SkyNest types I, II, III and IV. Theoretically, and if the buildingsize allows it, any of the SkyNest I, II, III and IV types could beplaced on a rooftop. However, in all of those types, the SkyNest wouldhave its dock area on the roof surface along with its pavement and thiswould require a building with an enormously large rooftop. The SkyNest Vis a 5^(th) type that differs from SkyNest types I, II, III and IV inhaving its dock for SkyQarts placed not on the rooftop, but on aseparate lower level that is one floor down from the rooftop. That lowerlevel dock is reachable for SkyQarts on the pavement areas by havingthem use one or more taxi ramps to reach that lower level. By placingthe dock on the lower level, and by being high enough above street levelobservers, a rooftop SkyNest V facility can quietly and efficiently useshorter pavements that align to any compass heading that suitable to theprevailing wind conditions.

In accordance with the calculated standard performance and trajectoriesof a SkyQart that is landing or taking off in zero wind on a pavementsurface equipped with a crash cushion, the nominal interoperable SkyNestV requires a square or round flat rooftop surface whose minimum diameteris at least 99 m. If a square surface of 99 m per side, the area of sucha SkyNest V would be 0.98 ha. A nominal SkyNest V must provide twosufficiently wide taxiing ramps to the lower level one floor down whereits dock facilities are located. Said SkyNest V must also provide one ormore express elevators to transport passengers and cargo at the dock toand from the street level below or to any of the other lower levels ofthe building or structure. The taxiing ramps are best positioned outsideof the 99 m diameter pavement surface area, in order to preserve itsfullest capability for landing along any compass heading.

The rooftop SkyNest V moves the SkyQart operations to a substantialheight above street level, and so can enable the use of a smallerSkyNest surface where the landing and departure paths need not occurabove and within the SkyNest boundaries because their acceptable noisespheres (ANSs) are imperceptible to observers at street level.

The nominal SkyNest V generally will incorporate the other core featuresof a surface SkyNest including the same sized facilities for docking,battery swapping, crash cushion, navigation, lighting, etc., except thatthe docking and battery swapping are performed on the lower level belowthat of the pavement level.

Fast Flaps System

The Fast Flaps System is an important component to this invention. Thedouble slotted wing flaps on all of the SkyQart aircraft enable theESTOL performance required of these aircraft. These flaps have a specialdesign innovation that enables them to fully retract in less than 0.5seconds. This is accomplished by their use of a special high instanttorque, non-cogging, thin, fast-accelerating pancake motor, housedinside the mid-wing bay, whose motor rotor serves as a crankshaft toprecisely move a set of pushrods the exact distance necessary tosimultaneously extend or retract their respective attached flap segmentson the right and left wing, to their ideal exact gap and overlappositions.

The extremely short pavement landing performance of the SkyQartsrequires rapid and powerful braking instantaneously after touch-downbecause in no wind conditions the vehicle will be traveling at 24 m/secat that instant. This rapid braking is made possible by the disc brakesand the regenerative mode of the electric motors in the wheels of themain landing gear. These wheelmotors are capable of powerfulregenerative braking but only under conditions in which substantialdownward weight is applied on the contact patch of the main landing geartires. Providing this substantial downward weight at the instant oftouch-down requires a near instantaneous cessation of wing lift, whichis accomplished for the SkyQart by a precisely timed and synchronizedrobotic automatic symmetrical retraction of its high-lift wing flaps inless than 0.5 seconds. This extremely rapid retraction is the essence ofthe fast flaps system and it is made possible by the combination of apancake motor with a direct crank linkage that can precisely,symmetrically and simultaneously move the left and right wing's extendedflap segments on their respective hinge pins into and out of their fullyretracted and nested position while using less than 180° of motor shaftrotation.

The high-lift wing flaps used in the fast flap system on the SkyQart areof the double-slotted semi-Fowler type, and the geometry of these flaps,according to credible research reports, can provide an unblown liftcoefficient that approaches 4.0. The SkyQart uses blown flaps that arepositioned directly downstream of the large propellers that are forwardof the main wing of the SkyQart so that the airstream accelerated by thepropellers will blow over the flaps and increase their effectiveness increating extra lift, with blown lift coefficients that can approach 7.0.The double slotted flap is comprised of two flap segments; a forwardflap segment and a rear flap segment. For the fast flap system on theSkyQarts of QUAD, the forward and rear flap segments each have acustomized and unique airfoil section tailored to efficiently directairflow downward and to closely fit the proprietary shape of the flapcove at the rear portion of the main wing airfoil. The main wing airfoilfor the fast flap system is the NASA/Langley LS(1)-0413 (GA(W)-2)general aviation airfoil whose maximum thickness is 12.9% of chord.Other airfoils may be used with a fast flap system on other aircraft andstill be encompassed by this fast flap system invention.

To minimize leakage drag, the forward and rear flap segments fit closelytogether when nested into their retracted positions inside the flap coveat the trailing edge of the SkyQart's wing. The internal spar andunderside skin of each of these flap segments is rigidly attached to aflap hinge strut that connects that flap segment to the aircraft atprecisely located hinge pins that attach to their respective externalunder-wing hinge fins. The hinge pin location for the forward flapsegment is a different location than that for the rear flap segment, andthis causes the forward and rear flap segments to swing on differentradii through different arcs as they are extended. This differentialarcuate movement causes the flap segments to separate from the wing andfrom each other at different rates as they are extended for the landingapproach. The exact hinge pin locations and the length of theirrespective flap hinge struts determine the relative movement of the flapsegments. The hinge pins are both located on a sturdy shared externalunderwing hinge fin that is rigidly and securely attached to thestructure of the wing's rear spar and lower wing surface just forward ofthat rear spar. The hinge pin locations for the forward and rear flapsegments are each located at a separate position below and aft of therear spar of the wing so that as the flap segments extend, the initialmovement of these flap segments is mainly aftward from the wing. Suchaftward, rather than downward, movement of the flap segments ischaracteristic of the so-called Fowler flap, but in this case theaftward movement is accomplished by a simple, low-friction hinge ratherthan by the traditional Fowler flap method of movement by rollers onflap tracks. This aftward movement increases the chord of the wing andthereby increases the effective wing area, which in turn, enhances lift.Once beyond their initial aftward extension, continued extension of theflap segments moves them mainly downward from the trailing edge of thewing and thereby increases the camber of the wing. The combinedincreases in wing chord and wing camber that result from full andoptimal extension of the flap segments have the effect of throwing airdownward and thereby provide a large increase in lift and drag duringflight at the operational angles of attack used during slow flight andapproach to landing. The actuation by use of simple hinges instead ofrollers on tracks enable these flaps to be retracted in less than 0.5seconds. The fast retraction process that is produced by preciserotation of the flap motor(s) is aided by aerodynamic forces attouchdown that tend to force the flaps up into their retracted, nestedposition.

The full and optimal extension of the flap segments positions them sothat an air gap or slot exists between the two flap segments and aseparate slot exists between the forward flap segment and the trailingedge of the wing. At full and optimal extension, these two slot gapseach have an optimal geometry in terms of the size of these gaps and theoverlap between both the flap segments themselves and between theforward flap segment and the wing. The gap measurement between the flapsegments is simply the shortest distance between the upper wing or flapsegment and the flap segment below. The gap is the length of a linedrawn from the lower surface of the trailing edge of the wing or flapsegment above to the nearest point on the upper surface of the flapsegment below. The overlap measurement between the flap segments is madeby first drawing an initial index line downward from the lower surfaceof the trailing edge of the upper wing or segment whose overlap is beingdetermined, making sure that the drawn index line is perpendicular tothe chordline of that upper wing or segment. Then, a second line isdrawn that is both parallel to that initial index line and tangent tothe leading edge of the lower flap segment. The overlap measurement isthen the shortest distance between the drawn index line and the drawntangent line. The gap and overlap sizes are expressed as a percent ofthe wing chord or % C. For each flap segment, it is the exactpositioning of the hinge pin locations and the length of theirrespective flap hinge struts that determine the slot gaps and overlapsthat, at full flap extension, provide optimal geometry for enhancinglift.

Dimensional details for the nominal interoperable embodiment of the fastflaps system expressed for the SkyQarts I & II in this patent are asfollows: The forward flap segment, at its full extension of 34°, has agap of 3.8 cm and an overlap with the wing trailing edge of 2.68 cm.Relative to the wing chord, “C”, of 142.3 cm at the flap root, theserepresent a gap of 2.68% C and an overlap of 1.89% C. The rear flapsegment, at its full extension of 56°, has a gap of 3.25 cm and anoverlap of 0.11 cm. These represent a gap of 2.29% C and an overlap of0.08% C. These gaps and overlaps closely fit the range of those that areoptimal for high lift according to page 41 of NASA CR-2443 published in1974. For the nominal SkyQart fast flap system geometry included in thisinvention, the fully extended flaps provide an increase in wing chord of20.8% along with a marked increase in wing camber. The SkyQart I & IIwing flaps have a span of 7.83 m. The maximum nested flap chord at theflap root (not at the fuselage midline) is 46.5 cm, which, relative tothe wing's total chord of 142.3 cm at that station, comprises a flapchord of 32.7% C. An acceptable range for flap chords in the SkyQart is28 to 38%. As the main wing tapers along its outer span, the flap chordtapers proportionately, remaining at 32.7% C. The flap span comprises71.35% of the SkyQart I or II's 10.97 m wingspan. From its nestedposition, the aft flap segment swings about its hinge pin through an arcof 56° to its full extension while the forward flap segment swings aboutits hinge pin through an arc of 34°. When fully nested, there is 18.64cm of the rear flap segment's upper surface that visibly extends aft ofthe wing trailing edge. Flap extension splays the two overlapping flapsegments apart longitudinally as they extend aft from the wing trailingedge. The wing chord at the flap root, with full flap deflection,increases from 142.3 cm to 172.0 cm, providing an increase at the flaproot of 29.7 cm in total wing chord. This results in a substantialincrease in wing area with full flap extension, adding nearly 1.86 sq m.A span of 2.54 cm separates the outboard end of the flap from theinboard end of the aileron.

The hinged movement of the flap segments is actuated by a pancake motorthat operates from inside the middle bay of the main wing. This motorrotates a crank with two separate crank pins—one pin for the forwardflap segment and one for the aft flap segment. These crank pins eachpush a separate pushrod that, in turn, pushes on the leading edge ofeach flap segment. Because it must move a greater distance, the crankpin for the rear flap segment is on a longer radius crank throw than thecrank pin for the forward flap segment, and thereby provides a longertravel for the rear flap segment when their common crank is swungthrough an arc of 120°. The robotic, software-controlled pancake motorcan accomplish this ⅔ of a revolution or 120° rotation required for fullflap retraction in less than 0.5 seconds, including the initial andterminal accelerations and jerk rates necessary for smooth and preciseoperation and consistent with GRACE. The motor can likewise fully orpartially extend both flap segments in nominally less than 0.5 seconds,although such rapid extension is prohibited an any airspeed above theairspeed for flap extension (V_(f)). Such rapid extension should only beperformed with caution due to sudden increased loads on the aircraft'sstructure. The radii of the crank throws can be exactly sized so thatthe roughly 120° crank rotation provides just enough pushrod travel todirectly move each flap segment to its ideal position. When coupled witha ground proximity sensor and ground contact sensor in the main landinggear, as well as to a sink rate sensor and propeller thrust sensor, thepancake motor in the wing can fully retract the wing flaps in idealsynchrony with the landing touchdown. That ideal synchrony is one inwhich the wing flaps are fully retracted and nested into the flap covewithin 0.5 seconds after the instant of touch-down. The full retractionof the flaps immediately after the landing touch-down instantly reduceswing lift so as to place a much greater downward force on the mainlanding gear tires, which, in turn, enables those tires to exert greaterbraking force on the pavement. The wheelmotor inside each main landinggear wheel will spool up the rotational speed of its wheel to match thedetected ground speed of the aircraft just prior to the moment oflanding touch-down. This will reduce both tire wear and tire chirp noiseand allow almost immediate braking to begin after touchdown. Theprecisely controlled wheelmotors with their anti-lock braking system canthen exert an exactly appropriate build-up and maximum amount of brakingforce to provide a minimum non-skid landing whose distance, decelerationand jerk rates that are tolerable to passengers, in accordance withGRACE.

To provide head clearance for pedestrians and crew, the flaps of thefast flap system remain retracted during the SkyQart's taxiing, dockingand other ground operations.

The SkyQart III has a fast flaps system whose operation and dimensionsare very similar to those of the SkyQarts I & II, except that it has anadditional wing center section of constant wing chord in which largeconstant-chord fast flaps are installed.

Alternative embodiments of the fast flap system concept are possible.Other types of flaps systems, including those that rely upon co-flowjets and circulation control may be used on other embodiments of theSkyQart and these are encompassed by this fast flap system invention,when they are used as high lift devices on SkyQarts and when their fullretraction or cessation of lift can be routinely accomplished in lessthan 0.5 seconds. Blown flaps are those whose lift is augmented by theblowing of air over them by propeller thrust or other means of blowingair such as compressed air or multiple small fans or turbines. Fast flapsystems may include single-slotted flaps, plain flaps, Fowler Flaps ofsingle, double or triple-slotted variety that move with rollers ontracks, as well as leading edge flaps and slats on the front of thewing, as long as their full retraction can be accomplished in less than0.5 seconds.

Active Main Landing Gear

The Active Main Landing Gear is an important component to thisinvention. The main landing gear of the SkyQart is connected to a fastand powerful actuator system that is able to position it at any of arange of desired positions, depending upon the situation. This actuatorsystem concept and process is called the Active Main Landing Gear. Itspurpose as an invention is to enable the very steep landing approachesand short take-offs of the SkyQart along with its requirement for exactheight positioning at the standard dock height.

In the embodiment presented herein, to reach its full dangle-downposition as occurs during final approach to land, there is 49.0° ofdownward swing of the main landing gear leg around its trunnion axiswhen measured from the static docking position of the main landing gearleg. From its static docking position, the landing gear can also berotated upward by 14.6° around its trunnion axis to place it in thetrailing cruise flight position. The total swing angle of the mainlanding gear leg is thus 49+14.6=63.6°.

The trailing portion of the wheel pant or wheel fairing must betruncated due to the extreme down angle of the main landing gear duringapproach to landing, so as to avoid scraping the fairing on thepavement. The fairing is mounted such that it offers the lowest dragwhen the landing gear leg is in the fully up trailing cruise flightposition.

The long-travel linear electro-hydraulic-magnetic damper used to movethe landing gear lever arm and thereby move each leg of the main landinggear operates autonomously in a fast-acting closed feedback loop toprecisely and actively position the landing gear at each instant duringlanding touch-down, with the positioning tailored to control theacceleration and jerk rates to tolerable levels while providing verylong travel (jounce) to absorb the loads from arresting the descent ofthe SkyQart from the instant of touchdown. This process is designed toprovide zero rebound after touchdown. It provides the gradual energyabsorption of the full jounce travel, which is completed in 1.08 secondsacross a jounce travel length of 0.65 m.

The automatic positioning of the main landing gear includes sensing andaccommodating the effects of its wheelmotors in generating additivetorque on the landing gear leg. The use of 40.64 cm diameter tiresrather than larger ones provides higher tire RPM, which can delivergreater efficiency of the direct drive wheelmotors and greater precisionin positioning of the SkyQart and its landing gear positions.

The Ultra-Quiet Propeller

Ultra-quiet Propellers are important components to this invention. Theultra-quiet propellers used on each of the nominal embodiments of theSkyQarts I, II and III herein are 3.05 m in diameter and have a maximumoperational speed of rotation of just 650 RPM. In addition, thesepropellers have a special electrically operated hub that cansimultaneously and rapidly and equally change the blade angle of each ofits seven blades. The hub achieves such blade angle change by having amechanism that can rotate each blade on its long axis at a nominal rateof up to 12 degrees per second. Such rapid blade angle changes enablethe propeller to rapidly change its level of thrust or drag to suit thephase of flight.

The ultra-quiet propeller combines two important inventions. The firstinvention is a multi-bladed propeller with high aspect ratio blades thancan deliver the thrust required for take-off and climb while emitting nomore than 35 dBA of noise at a 40 m sideline¹⁴. The second invention isthat same propeller having a controllable hub that is capable ofprecisely and equally changing each blade's angle at a rate of more than12° per second, which enables the very rapid transition from thrustingmode to wind-milling mode to reverse-thrusting mode. The nearlyinstantaneous transition from thrust to reversal of thrust enables theextremely short landing distances and agile steep descents duringapproaches to landing.

The extremely low noise achieved by this propeller is due to itscombination of very low tip speeds with seven high-aspect ratio, stiff,vibration-resistant, laminar flow blades that have reduced tip vorticesand that are pitched to deliver high lift coefficients in accordancewith the author's existing patent number U.S. Ser. No. 10/415,581B1.

The special ultra-quiet, multi-bladed propellers used in QUAD have alarge diameter of more than 213.4 cm and have take-off and cruiserotational tip speeds that are limited to below 152.4 m/sec. Thesepropellers may vary in number from the nominal interoperable twopropellers on the SkyQarts I and II to the nominal interoperable threepropellers used on the SkyQart III. Alternative embodiments of theSkyQarts may have a number of propellers of about two or more, aboutthree or more, about four or more, about six or more or any numberbetween and including the numbers of propellers provided, while it ispreferred that the number be two for the SkyQarts I and II and three forthe SkyQart III because these offer the lightest and simplest means tocreate blown wing flaps. Each nominal interoperable propeller has sevenblades as in the preferred embodiments presented herein. Alternativeembodiments of the SkyQarts may have a number of propeller blades with aconceivable range of about three or more, about four or more, about fiveor more, about six or more, about seven or more, about eight or more,about nine or more or any range between and including the numbers ofpropeller blades provided, while it is preferred that the number beseven for all SkyQarts with a preferred range of six to eight becausethese offer the lightest weight variants that can still achieve theextreme low noise emissions that are necessary.

Electric Payload Cart (EPC) Seat Latching Tracks and Latching Pins

The Electric Payload Cart (EPC) is an important component to thisinvention. The EPC is designed as a standard sized device withstandardized attachment tracks. It can be loaded and latched into anySkyQart or onto the top of any RDC in order to carry the EPC'slatched-on payload from point of departure to doorstep destination. Thenominal interoperable EPC can carry a 265 kg payload. Alternativeembodiments of the EPC may carry payloads within a conceivable range ofup to 260 kg, to to 280 kg, up to 315 kg or any weight between andincluding the weights provided, while it is preferred that the weight bethe nominal interoperable 265 kg with a preferred range of 260-280 kgbecause this provides a workable combination of practicality, manageablepower demand, structural loads, and compatibility with the most commonpayloads to be hauled. The EPC is sized to provide for hauling a widevariety of different payloads of common types while still fitting insideany SkyQart and atop a standard RDC. It is important that the EPC havestandardized size, height, shape, capacity, seat-latching trackdimensions and track spacings in order to enable standardized attachmentfixtures on seats, cargo bins, latching racks and other cargo haulingattachments that carry various common and uncommon payloads in the QUADsystem. Nominal interoperable dimensions for these parameters areprovided as standards herein. Other alternative standards may be used,but these would only make sense to the concept and processes of the QUADsystem if they were part of system-wide standards settings that werealso made compatible with the dimensions and sizes of RDCs and SkyQarts.

The standard EPC trapezoidal platform that fits correctly inside theSkyQart is 144.8 cm long and 103.2 cm wide at its rear edge. Thisstandard platform narrows symmetrically at the forward portion of thecart to have a width at its forward or front edge of just 71.12 cm. Thenarrowing of its trapezoidal platform begins at 91.44 cm forward of therear edge of the platform, a station where, when pin-latched into itsnominal interoperable position in the SkyQart, the inside diameter ofthe AFP is 146.7 cm. The EPC has a 119.4 cm wheelbase. Its front trackis 58.1 cm wide and its rear track is 88.9 cm wide. The front wheels aresturdy swiveling castors. The rear wheels are autonomously controlledwheelmotors. Each of the four 12.7 cm diameter wheels are set 12.7 cmfrom the fore or aft edge of the cart¹⁵. The EPC has no suspensiontravel and therefore has a nominal and consistent 2.54 cm of groundclearance, an important dimension that is predicated both on its need tomaximize passenger headroom inside the SkyQart's AFP and on the need forthe EPC's surface deck to have a consistent height above the cabin floorof the SkyQart. The 2.54 cm ground clearance is sufficient because EPCsnormally only operate on the flat smooth dock, and the flat smoothfloorboard surfaces of the SkyQarts and the RDCs, which are grooved toaccommodate the standardized tire spacings of the EPC. Each tire on theEPC has its sidewall just 5.2 cm from the lateral edge of the EPC.

Each rear wheel of the EPC is attached to a powerful wheelmotor that canprovide precise rotation as needed for steering and positioning of thecart on the dock and into and out of the SkyQart or RDC. The EPC hasfour separate sets of identical 6.86 mm diameter holes arranged in alinear array with equal 25.4 mm spacing between these holes with anarray located along both the forward and aft portions of both the portand starboard sidewalls of the EPC. Each of these four arrays consistsof four such holes that are horizontal and are each 12.7 mm deep. Theseholes serve as receptacles for the four separate 6.35 mm diametersolenoid-operated latching pins that fixate the sides of the EPC to theinterior of the SkyQart's AFP and to the floor of the RDC. There are twoforward solenoids and two aft solenoids, all with latching pins. Thisarray of solenoids are structurally attached to the interior of theSkyQart's AFP structure or to the sides of the RDC's surface deck,respectively. The center of the latching pins of the forward and rearsolenoids are a standard 77.5 cm apart. These four solenoid pins arenormally extended and require application of an electrical current inorder to retract, but they can also be retracted and disengaged manuallywith a pull-ring that can be latched into the pin-disengaged positionwhen pulled.

Side-to-side restraint of the EPC is augmented by the sturdy solenoidbody itself. The means of manual release, when necessary, is by both ahidden external electrical push-button to electrically actuate thesolenoids or by a hidden pull-cable that is ganged to the pull-rings ofall four solenoids. One such commercial example of such a solenoid isdescribed here¹⁶.

The aft-most of these four 6.35 mm holes for the solenoid latching pinsin the sidewalls of the EPC are centered nominally 38.1 mm forward ofthe cart's trailing edge on both its port and its starboard sides, atthe midpoint of the cart's sidewall height. An identical array of thesefour holes is present on both sides of the cart at a forward locationnear the point at which the cart's trapezoid-shaped surface tapers inwidth. The forward most of these forward four holes is located 88.9 cmforward of the cart's trailing edge. These four holes provide adjustmentof the location at which the EPC is pin-latched inside the aircraft sothat the SkyQart's center of gravity can be adjusted as needed. For boththe SkyQart and the RDC, the inner surface of the rectangular solenoidbody whose pin latches the EPC is located 3.81 mm laterally from thesidewall of the EPC. This narrow 3.81 mm clearance is important to therapid loading and unloading of the EPC. A larger clearance would lead torattle and looseness of the pin-latching and a smaller clearance wouldcause scraping and friction during loading and unloading.

The EPC has its own low-profile rechargeable and swappable battery packalong with an on-board navigation system. This navigation systemoperates using detect-and-avoid hardware and software similar to thoseused in driverless cars, allowing it to move autonomously around thedock and into and out of the SkyQarts there. The EPC has a multi-sensorprecision positioning system that is integrated with the navigationsystem and that includes line-following software that enables it toprecisely dock into SkyQarts and onto RDCs.

The top surface of the EPC has six separate longitudinal seat latchingtracks whose size, shape and spacings are standardized herein for thepurpose of facilitating the attachment of various types ofpayload-holding devices, including seats, Qusheats and cargo haulingattachments. These payload-holding devices are attached to the EPCbefore it gets loaded with a payload and before it gets pin-latched ontoa SkyQart or RDC. These payload-holding devices may include passengerseats of various types, baggage bins, cargo bins, latching racks for theattachment of out-sized freight and building materials and other cargohauling attachments. To enable interoperability, the locations anddimensions of the seat latching tracks are standardized on all EPCs interms of their shape, height, width, thickness, contour, hole size,material strength and spacing to make for uniform attachmentspecifications for the various types of payload. The shortened outermostseat latching tracks on the cart are near the cart edges and aretruncated at the forward portion of the cart where the planform of thecart platform necessarily tapers symmetrically in order to fit insidethe AFP. The centers of these outermost tracks are 99.1 cm aparthorizontally. At a distance of 25.4 cm inboard of the center of theseoutermost seat latching tracks are the center of the EPC's medium-lengthseat latching tracks, which terminate at the forward wheel casters. At adistance of 8.9 cm inboard from the medium-length seat latching tracksare the full-length seat latching tracks. The center of the full-lengthseat latching tracks are 30.5 cm apart horizontally, and are spacedequidistant from the longitudinal centerline of the EPC. These exactdimensions of this array of seat latching tracks serve as a nominalinteroperable set of standards to which a wide variety ofpayload-holding devices can be built so that they can be latched onto anEPC. These devices include seats, cargo bins, med-evac litters,wheelchairs, bicycles, scooters, generators, air compressors, solarpanels and various combinations thereof as well as latching racks andplatforms for a wide variety of other out-sized payloads. The size ofthe EPC itself, both laden and un-laden, is designed to also fit ontothe surface of the Robotic Delivery Cart (RDC) and to pin-latch onto itin the same fashion that it fastens to the interior of the SkyQart,i.e., by solenoid pin-latching into the receptacle holes on thesidewalls of the EPC.

The EPC's battery pack is standardized for the QUAD system at a nominalsize of 6.35 cm H×22.9 cm W×30.5 cm L. It is mounted between the innerseat latching tracks of the EPC, straddling its centerline, on top ofits surface deck, with its rear face 2.54 cm forward of the rear edge ofthe EPC. Just forward of this battery pack is mounted the EPC'snavigation hardware pack, whose dimensions are 6.35 cm H×22.9 cm W×6.35cm L.

The one-seat and two-seat payloads when pin-latched onto the EPC providecloseable small carry-on baggage bins both in front and in back of theseat. The bin in front of the seat provides for access to personal itemsduring flight. For two-seat payloads, there are two front baggage binsand two rear ones. Each front baggage bin and aft baggage bin is atleast 58.4 cm H×36.8 cm W×25.4 cm L and can accommodate one airlinestandard carry-on bag of 55.9 cm×35.6 cm×22.9 cm, so that each passengerin a two-seat SkyQart can carry two airline standard carry-on bags. Thehinged lid of the front baggage bin contains an accessible touch-screentablet computer whose dimensions are 30.5 cm×22.0 cm×0.69 cm. It has a32.8 cm diagonal screen (a popular size for a computer tablet) andoffers high-speed wi-fi internet access and a USB or other popularstandard port jack. When the EPC is fitted with its maximum of threeseats, space limitations demand that there is no room for baggage bins.In the case of an EPC with a three-seat payload, the forward passengermust fold his or her legs onto the leading edge of the cart when it isrolling along the dock. Other limitations of the three-seat EPC are thatit can be carried on top of the RDC for short trips in good weather, butunlike the one or two-seat version of the EPC, the three-seat version istoo large to be covered with a rain roof on the RDC. The two andthree-seat configurations of the EPC can offer a thin, lightweight,retractable, translucent plastic privacy screen between the side-by-sideseats and this screen can also serve as a breath and sneeze barrier forsocial distancing.

In order to carry out-sized or larger freight payloads such as 1.22m×2.44 m sheets of plywood, 155.7 cm solar panels or 5.1 cm×30.5cm×365.8 cm long lumber, the rear hatch of the pod can be removed andreplaced with an alternative “stretched” version of the rear hatch thatincorporates a 61.0 cm L×156.8 cm W cylindrical extension to increasethe cabin volume of the SkyQart. This extension includes an extension ofthe cabin floor to maintain the ability to roll payload-laden EPCs intoand out of the SkyQart. Hauling such large building materials will alsotypically require that a latching rack be attached to the seat latchingtracks of the EPC in order to position the building materials closer tothe central axis of the AFP such that the bottom surface of the buildingmaterials is 30.5 cm above the cabin floor's upper surface. This 30.5 cmdimension positions the building materials such that they can occupy themaximum available length inside the AFP. In some cases, an EPCespecially dedicated to hauling building materials may be used. Thatbuilder's version of the EPC retains its standard trapezoidal planform,wheelbase and track, but has no seat latching tracks; instead it has alatching rack or other truss-braced, purpose-specific frameworkpermanently attached to the EPC's deck surface. An example of abuilder's EPC with a purpose-specific framework would be once with acradle that fits standard 208.2 liter (55 gallon) drums whose 59.7 cmdiameter and 87.6 cm length would allow for two such drums to easily fitwithin the SkyQart AFP's interior space.

QUAD cargo bins that attach to the EPC come in three standard versions.These standard versions are designed to maximize interior volume whilestill fitting inside the AFP when attached to the EPC. Alternative cargobins could be devised using different dimensions if they retain theability to fit inside the AFP, whether attached to an EPC or not. Oneversion, the Main Cargo Bin, has a single large cavity for holdingseveral parcels of medium to large items. A second version of cargo binis used to expand this Main Cargo Bin by adding two Extension Bins toit, one at the front and one at the back. Each Extension Bin isnominally 63.5 cm L×63.5 cm H×63.5 cm W and is centered on the long axisof the AFP. The rear Extension Bin has an aft door for inserting longobjects. When added onto the Main Cargo Bin dimensions, these ExtensionBins provide an interior dimension that is 2.44 m long. A third versionof cargo bin for the SkyQart is the Locker Bin, which is a Main CargoBin that is modified to contain several different sized lockers withdigital key locks that can be unlocked by the intended recipient of eachparcel in the payload. All of these standard embodiments of the QUADcargo bin containers attach to the standard EPC by the same mechanism asdo passenger seats, using solenoid actuated latching pins into the seatlatching tracks of the EPC.

In the three-seat version of the EPC, the seats are positioned so as toaccommodate rear passengers who are the standard size for the 95^(th)percentile human at 188.0 cm tall. The seat for the forward midlinepassenger is positioned to accommodate a person only up to 177.8 cmtall. This sizing of people on a three-seat EPC produces a total heightof 113.8 cm from the top of the tallest passenger's head to the surfaceof the dock. This is the same height dimension as for thepassenger-laden standard two-seat version of the EPC. This 113.8 cmheight allows any EPC loaded with passengers to easily fit underneaththe tailcone of any SkyQart parked at the dock, where the clearance is198.1 cm. By having the EPCs move underneath the aircraft tailcones asthey board and deboard the SkyQarts, their transit time on the dock canbe minimized, and the land parcel size necessary for the SkyNest can bekept small.

The three-seat version of the EPC can be carried in each of the twofuselage pods of the dual-AFP SkyQart III, resulting in the maximum ofsix passenger seats in that aircraft, provided that the passengerweights and their personal items in each pod are kept within specifiedweight and e.g. limits. The baggage space available in the three-seatversion of the EPC is necessarily limited and consists of either placingpersonal items under one's seat or holding them on one's lap for theduration of the flight. In some cases, a threesome traveling togethermay choose to arrange for a SkyQart III to carry them on a three-seatEPC in one of its AFPs, while its other AFP carries an EPC that cancarry all of their baggage, packages or cargo.

Cargo normally gets pre-loaded at a dedicated Cargo Service facility onthe dock of the SkyNest rather than on the dock area where passengersare boarding near their SkyQart's appointed dock station. The standardembodiment of the seat latching tracks on the EPC allow the conversionof EPCs to various payload purposes. However, the Cargo Service facilitymay have some specialized alternative embodiments of the EPCs that haveno seat latching tracks in order to carry unusual types of cargo. Inpractice, most EPCs will continue in service as either seat-equipped orcargo bin-equipped, with modifications for carrying unusual payloadsbeing rather uncommon. If carrying building materials, the EPC will havea cargo version that allows it to carry and deliver larger items such as1.22 m×2.44 m sheets of plywood or sheetrock, or various lengths offraming lumber. The standard EPC seat latching tracks can also allow theEPC to carry ground mobility devices such as wheelchairs and walkers,along with electric scooters, bicycles of low height, etc., providedthese items are fitted with compatible seat latching track adaptors.These ground mobility items may fit side-by-side with a passenger seaton an EPC. Some items too large to fit alongside a seat will have to becarried alone as a single fare on their own EPC.

The EPC inside a SkyQart fuselage pod can be off-loaded using a rampwhen a dock or RDC is not available. This off-loading is facilitated byhaving the active main landing gear retract to lower the belly of theAFP to within 1.3 cm above ground level with the nose gear at itsnominal height, which creates a 5° nose-up fuselage angle, so that theEPC can roll out the back of the AFP onto the ground without scrapingits belly.

To ensure passenger headroom and no head-bump, EPC seats canautomatically recline slightly during the on and off loading of theSkyQart at the dock.

EPC Payloads

As stated above, an EPC, with its nominal 119.4 cm wheelbase, can carrya variety of payloads consisting of both people and goods within itsweight limits. It can also carry lumber, fuel and building materials. Acommon use for the SkyQart I or II is to carry two passengers seatedside by side on reclining seats that are equipped with the Qusheat ridecontrol seat. The two-seat version normally has its EPC pin-latched intothe SkyQart such that the front edge of its seat-mounting bracket is atFS 206.0 cm which places the center of gravity of the crew at FS 228.2cm, a location that helps to keep the SkyQart's center of gravity withinacceptable limits.

In such a case of two-seats, each passenger on an EPC is provided withtwo separate baggage compartments, one in front of the seat and onebehind the seat. Each compartment has external dimensions of 25.4 cmL×58.4 cm H×36.8 cm W which allow a standard size domestic airlinecarry-on baggage item of 22.9 cm L×55.9 cm H×35.6 cm W to fit inside it.The front baggage compartment has a closeable lid that contains atouchscreen computer tablet that offers free wi-fi internet service. Therear baggage compartment is hinged so that it can recline rearward 34°to enable the passenger seat to recline 30° rearward for sleeping. Theforward baggage compartment is mounted to the EPC with a 45° tilt-backangle to aid accessibility for the seated passengers. The rear baggagecompartment is mounted to the EPC with a 27° tilt-back angle. Thesebaggage compartments are removable and they pin-latch onto the seatlatching tracks of the EPC. One or both of these baggage compartmentscan be removed to accommodate exceptionally large passengers.

The nominal removable 55.9 cm L×114.3 cm H×121.9 cm W flotation module#1, when removed from a two-seat SkyQart, provides adequate space insidethe rear hatch of the AFP for the reclining seat and rear baggagecompartment to recline to their respective limits. This flotation moduleis nominally 121.9 cm wide at the waterline of the seat armrests butnarrows to only 101.6 cm wide at the waterline of the passenger'sshoulders. The bottom of module #1 is aligned with the cabin floor ofthe SkyQart.

In the case of a SkyQart fitted with an EPC that has three Qusheat ridecontrol seats, there is no room for reclining the front seat and thereare no baggage compartments. The three-seat SkyQart must fly withflotation module #1 removed. With three-seat EPCs, passengers must stowtheir personal items under their seat or on their lap.

All EPCs carrying payloads in SkyQarts have their weight and center ofgravity automatically calculated prior to boarding the SkyQart so as todetermine the appropriate fore-aft position for latching the EPC insidethe SkyQart. Said weight and center of gravity are calculated from dataobtained from the EPC's on-board strain-gauges that are attached neareach of its four wheels.

The EPC can alternatively be configured to carry not passengers butvarious sizes of cargo bins pin-latched to its seat rails. All cargobins are sized so that when fastened to an EPC, that EPC/cargo bincombination will fit inside the interior cabin space of a SkyQart's AFP.A nominal interoperable embodiment of such cargo bins is comprised ofthe Main Cargo Bin, which is a large central 121.9 cm L×91.4 cm H×106.7cm W bin. The Main Cargo Bin can be joined to two smaller ExtensionBins, one fore and one aft, each of which is nominally 63.5 cm L×63.5 cmH×63.5 cm W. Together, these three joined bins can offer a standardSkyQart an interior fore-aft dimension of 2.44 m in order to haul longobjects. Alternatively, the large central Main Cargo Bin can be carriedalone, in which case flotation module #1 can be installed into the rearhatch. To fit fully inside the standard AFP, the leading edge of thelarge central Main Cargo Bin is positioned at FS 141.76 cm where theinside diameter of the AFP is 131.75 cm. In such case, the aft face ofthe large central Main Cargo Bin is 15.24 cm forward of the AFP'shatchline and its bottom surface is elevated 10.16 cm above the topsurface of the EPC and 14.6 cm above the cabin floor. The smaller 63.5cm cubical Extension Bins in this case straddle the axial center of theAFP, which places their bottom surfaces 8.26 cm above the bottom surfaceof the large central Main Cargo Bin. The combined three cargo binsattach to the seat latching tracks of the EPC with four separate 10.16cm H×10.16 cm L×4.45 cm W brackets that contain solenoids with latchingpins that are also pull-pins. The leading edges of the forward pair ofthese brackets are at FS 157.8 cm. The leading edges of the two rearbrackets are at FS 253.5 cm. The two forward brackets attach to theinnermost seat latching tracks while the two rear brackets attach to theoutermost seat latching tracks.

If stacked on a special latching rack that fits on top of the EPC andthat has its top surface nominally 30.5 cm above the cabin floor, theSkyQart can carry 3.05 m lengths of standard lumber, whose actualdimensions are 3.81 cm H×28.58 cm W, if that lumber is stacked sixboards high and two boards abreast on that latching rack. This wouldcomprise a load of twelve boards, each of which weighing 21.8 kg andtotaling 261.3 kg. To obtain an acceptable center of gravity for theSkyQart with this lumber payload, its forward edge must be positioned asfar forward as possible, at the aft face of the bulkhead located at therear limit of the nosegear well, which is at the FS 68.6 cm, measured asthe distance aft of the datum, which datum is the external tip of thenose of the AFP. At FS 68.6 cm, the inside diameter of the AFP is 88.1cm. Alternatively, the latching rack could carry a spare SBP of 145.15kg. Alternatively, the latching rack could carry a 54.9 cm tall stack oftwelve SunPower solar panels¹⁷, each of which weighing 18.6 kg to equaltotal of 223.2 kg. These solar panels each have nominal dimensions of155.7 cm×104.6 cm×4.6 cm. The leading edge of this stack of solar panelswould be positioned at FS 134.14 cm where the AFP's inside diameter is126.0 cm. Such a payload of solar panels, at 22.7% efficiency, have amaximum power of 370 watts each and so when arrayed correctly couldcomprise a power station with a potential to produce more than 4.4 kW.The EPC on its latching rack could alternatively carry two 208.2 liter(55 gallon) drums of dimensions 59.7 cm diameter and 87.6 cm height, ifthese drums were lying on their sides end-to-end and were partiallyfilled to a weight within the capacity of the SkyQart's payload. Theleading edge of these two drums would be positioned at FS 123.24 cmwhere the AFP's inside diameter is 120.5 cm. The EPC could alternativelycarry or a Honda 5.5 kW generator of 118.8 kg whose size is 119.9cm×70.1 cm×72.1 cm, along with three gasoline cans, each of which has18.9 liter capacity and whose size is 35.1 cm×27.9 cm×36.3 cm and whoseempty weight is 0.91 kg each.

The AFP can be fitted with a nominally 61.0 cm long cylindricalextension to become the cargo axisymmetric fuselage pod. Thiscylindrical extension piece is attached at the rear hatch opening of theAFP. Using the cargo axisymmetric fuselage pod and an EPC with alatching rack, the SkyQart could carry six sheets of 1.22 m×2.44 mplywood of 2.86 cm thickness, with each sheet weighing 38.3 kg,comprising a 230.0 kg payload. This stack of six sheets of plywood wouldhave its leading edge positioned at FS 145.5 cm where the insidediameter of the AFP is 131.45 cm. Also, with such an extended cargoaxisymmetric fuselage pod, the aforementioned load of stacked lumbercould each instead be of 3.66 m length rather than 3.05 m length. Insuch case, the stack of lumber would extend from FS 68.6 cm to FS 434.3cm where the AFP's inside diameter is 78.4 cm.

The EPC is typically pin-latched to the AFP in the standard SkyQarts byfour separate 6.35 mm diameter round solenoid pins, which pins arenormally extended from their solenoid actuator. There are two solenoidactuators on each side of the AFP and the centers of their pins arenominally 77.5 cm apart in the fore and aft direction. Each solenoidactuator is nominally 4.45 cm wide (spanwise) by 4.45 cm long by 3.8 cmtall. The aft solenoid actuators have their pin centerline at 3.8 cmforward of the plane of the AFP's rear hatch door. The forward solenoidactuators have their pin centerline a compatible 81.3 cm forward of theplane of the AFP's rear hatch door. For the uncommon case of using acargo axisymmetric fuselage pod, there are two additional intermediatesolenoid pin actuators in each AFP, one on either side, and the pincenterlines of these are placed nominally 25.4 cm aft of those of theforward solenoid pin actuators. In addition, for the case of the cargoaxisymmetric fuselage pod, there are two additional aft solenoid pinactuators, one on either side in the cylindrical extension piece, andthese can be paired with the intermediate solenoid pin actuators topin-latch EPCs at locations that are further aft inside the cargoaxisymmetric fuselage pod. These intermediate solenoid pin actuators arestandard equipment in each AFP and the aft solenoid pin actuators, whichare located at the standard 77.47 cm aft of the intermediate ones, arestandard equipment in each AFP cargo extension piece.

Each solenoid actuator body has a nominal 3.81 mm gap from the side edgeof the EPC, when the EPC is positioned inside the AFP.

The EPC with any of its various payload configurations can also bepin-latched atop the RDC and can be off-loaded from the RDC onto avariety of other surfaces. It can be off-loaded onto a truck dock, theroof of an autonomous car, the bed of a pickup truck, or other vehicle.

The autonomous robotic EPC has a manually operated “Go-button” thatalerts its on-board autonomous robotic control system that it is readyto roll on the dock to its next destination. The Go-button is to bepressed by a passenger who is seated and seat-belted onto the EPC onlywhen that passenger has completed all of his or her optionalpreparations for travel, including stowing of baggage and personaleffects, combing hair, checking cellphone messages, waiting for aride-sharing person, if any, to arrive and be seated and seat-beltedaboard said EPC, etc. The time spent on such optional preparations isherein called a “prep-delay” and, by policy, it is to be minimized inorder to achieve a high capacity throughput for the QUAD system. Theprep-delay is measured from the appointed and reserved on-demanddeparture time of the SkyQart. Prep-delay is zero when the EPC Go buttonis pressed and the EPC has rolled into and securely latched to theinterior cabin of its docked SkyQart at any time prior to the appointedand reserved on-demand departure time of that SkyQart. Pressing theGo-button will have no effect unless all seatbelts on the EPC aredetected as being securely fastened. As soon as secure pin-latching ofthe EPC into the SkyQart cabin or onto the surface deck of an RDC iscompleted, the wheelmotors of the EPC are immobilized and the SkyQart orRDC can begin its scheduled trip. The policies that minimize prep delaycomprise potential flight cancellation and substantial user cancellationsurcharges whenever a prep delay exceeds a reasonable limit. When aSkyQart lands and docks with precise alignment to an aircraft dockingstation with its rear hatch open, the SkyQart's autonomous controlsystem detects that successful docking and immediately and automaticallyunlatches the pin-latches that secure the EPC to its cabin floor. Thisunlatching is detected by the EPC and is interpreted by it as if theEPC's Go-button had been pressed, so that the EPC will then be activatedto exit the SkyQart cabin and roll onto the dock to its next designated,intended destination. Likewise, an unlatching of the EPC from thesurface deck of a docked RDC activates that EPC to roll off of the RDConto the dock and onward to its appointed destination.

For cargo payloads, the Go-button is nominally to be pressed by theperson on the dock area who performs the loading and closing of theEPC's cargo bin(s) and it is pressed only when said loading and closingis complete and the EPC is ready to go to its appointed destination. Asis the case for a passenger flight, avoiding prep-delay means that theGo-button for an EPC that is carrying a cargo payload is to be pressedprior to the appointed and reserved on-demand departure time of itsappointed SkyQart so as to allow that EPC to load and latch into saidSkyQart prior to said departure time. By policy, some cancellation orsurcharge fees can likewise be assessed for cargo payloads that haveexcessive prep-delays. For EPCs with a cargo payload, when the SkyQart'sautonomous control system detects that a precise and successful SkyQartdocking has been achieved, it then automatically unlatches thepin-latches that secure the EPC to its cabin floor. This unlatching isdetected by the EPC and effectively activates the EPC's Go-button sothat the cargo laden EPC will exit the SkyQart cabin and roll onto thedock to its next appointed destination.

The loading and unloading of an EPC to an RDC proceeds in the samefashion as for the loading and unloading of an EPC to a SkyQart. Thatis, pressing a Go-button can initiate movement of an EPC on the dock toroll to a docked and waiting RDC and cancellation of EPC movement occursonce it is pin-latched onto the RDC. When the RDC reaches its appointeddestination, it automatically unlatches the pin-latches holding the EPCand this activates the EPC to roll off of the RDC and onto the dock fromwhich it proceeds onward to its next destination.

The Robotic Delivery Cart (RDC)

The Robotic Delivery Cart (RDC) is one of the important inventions thatmake QUAD possible. The fundamental importance of the RDC is not itsrobotic navigation or its versatile residential delivery, it is theRDC's interoperability with the other electric vehicles in the QUADsystem by virtue of its standardized track, wheelbase, height,dimensions, batteries, speed, precision positioning system along withthe standard embodiment of the EPC latching system. The RDC's standards,along with its long-travel scissor jack enable the RDC to act as if itis part golf cart and part forklift while being compatible with QUADSkyQarts, EPCs, trucking, cargo, med-evac, and last-mile deliveries ofall types, including those in bad weather and for disabled people. Thestandard embodiment of the RDC presented in this invention will havemany future variations and refinements and will evolve over time, but anRDC needs to retain dimensional and operational standards such as thosedescribed in the embodiment herein in order to be compatible with theQUAD dock and SkyQart vehicles. The RDC is mainly intended to carry in atype of piggyback transportation, a payload-laden EPC to its intendeddoorstep destination, but it is also specially equipped to service anySkyQart that happens to need its EPC removed and replaced or its SBPswapped when parked at a location other than at a QUAD aircraft dockingstation. In the unusual event that it is necessary, the RDC can use itsextensible heavy-duty battery pack drawer slides in order to unload abattery pack from a disabled or stranded SkyQart on the aircraftpavement ramp at a SkyNest.

When an RDC onloads an EPC, the surface deck of the RDC is set to thesame height as the bottom of the EPC's tires. The RDC deck is normallyset at the nominal interoperable height of 47 cm above ground level forthis maneuver because that is the standard height of the surface of thedock at a SkyNest. The EPC loads from the dock surface onto the top ofthe surface deck of the RDC by backing up, once its tires are inalignment with the tire grooves provided in the RDC's surface deck. Whenit reaches the proper position on the RDC deck, the EPC is pin-latchedonto the RDC by four separate solenoid latching pins. When carrying anEPC loaded with two passengers, the RDC provides a windscreen that canbe rotated to the rear of the RDC during the on-loading of the EPC. Inwindy and rainy conditions, the RDC's windscreen can extend inaccordion-like fashion to become a rain canopy to protect thepassengers, provided that its EPC is loaded with no more than twopassengers seated side-by-side. Due to safety regulations andneighborhood electric vehicle licensing, the RDC is not recommended forcarrying an EPC that is loaded with three passengers, unless for shortdistances in dry weather. Alternatively, the RDC can on-load and carryan EPC that is loaded with a Main Cargo Bin, or a Main Cargo Bin withboth a forward and an aft accessory Extension Bin, each of which adds63.5 cm to the available length. With such cargo bin extensions, thecombined interior cargo dimension becomes 244 cm long. The RDC can alsoon-load and carry an EPC with a latching rack loaded with out-sizedbuilding materials from either a standard SkyQart, or from a SkyQartwith an extended cargo axisymmetric fuselage pod, though the length ofthose materials precludes use of the windscreen and bubble rain roofcanopy. These outsized building materials could include, for example,5.08 cm×30.48 cm lumber or 1.22 m×2.44 m sheets of plywood. An RDC canalso serve as a courier to deliver spent battery packs to a nearbycharging station and bring freshly charged battery packs back to a dockor to a stranded vehicle. Like a forklift, the RDC can stack heavystandard battery packs onto a nearby dock site or pallet. The RDC canon-load and off load both EPC and standard battery packs autonomously atdocks of various heights as needed.

The scissor jack on the RDC utilizes nominally 7.6 cm diameter and 3.18cm wide high capacity cast polyurethane wheels on 1.27 cm diameter axlessuch as this example¹⁸. The RDC standard scissor jack has 4 separatescissor blades, two on the port side and two on the starboard side, andeach such blade has a nominal length of 159.18 cm between its end axles.The four aft end blade axles have a nominal diameter of 12.7 mm, andeach holds a pair of the 7.6 cm diameter by 3.18 cm wide castpolyurethane wheels, each of which has a wheel capacity that isnominally 272.2 kg. The two bottom forward blade end axles each pivot ona nominal 11.11 mm diameter bolt in a ball-bearing hinge that isattached to a stationary gusseted flange that is structurally attachedto the forward outer bottom portion of the steel frame of the RDC. Theother blade end axles on the forward ends of the upper scissor bladeseach pivot on a nominally 11.11 mm diameter bolt in a ball-bearing hingethat is attached to a gusseted flange that is structurally attached onthe underside of the forward outer portion of the RDC'sheight-adjustable surface deck. There are two separate but identicallinear actuators for the scissor jack, and each of these is mounted to a11.11 mm pivot bolt that connects its forward end to the bottom of thefront portion of the chassis of the RDC. At its opposite (rear) end, theram of each linear actuator is structurally attached with a nominally1.27 cm shear bolt to a yoke that pulls horizontally on the 1.27 cmdiameter axles of the scissor jack's rear 7.6 cm diameter wheels. Thesetwo actuators work in unison to autonomously move the scissor jack toposition the height of the RDC's surface deck. Each actuator offers anominal 48.3 cm of travel, which is enough to move the scissor jack fromits fully collapsed position where the RDC surface deck is nominally35.6 cm above street level, to its fully extended position where the RDCsurface deck is elevated to nominally 142.2 cm above street level. This106.7 cm range of heights for the RDC surface enables it to bepositioned so as to off-load its EPC onto a variety of surfaces,including onto commercial truck loading docks and truck rear doors, theback of pick-up trucks, etc.

Each of the RDC's scissor jack's polyurethane wheels can accommodate anominal load of 272.2 kg. For load spreading, dual wheels are used atthe rollers at the bottom rear axles of the scissor jack and widelygusseted bearing flanges with 11.11 mm bolts are used at theball-bearing hinges located at the forward ends of the scissor bladeswhere they attach to the steel frame of the RDC.

The height of the top deck of the RDC is normally maintained at thestandard 47.0 cm dock height by its electric scissor lift mechanism andthis height is continuously adjusted and tuned to maintain dock heightas loads are transferred onto and off of the RDC. Alternatively in somelower cost RDCs, the outer corners at the front of the metal chassis ofthe RDC could contain extendable vertical legs that serve as manually orelectrically-operated screw jacks that extend to touch the ground andthereby lock the height of the RDC at the dock height in order tomaintain that height as loads are transferred onto the RDC. The range ofdock heights at truck docks¹⁹ that could be expected to be encounteredare accommodated by the extension of the RDC's long scissor lift arms,which can lift its top deck to as high as 142.2 cm above the groundlevel. The nominal 142.2 cm height coincides with the standard height ofmost types of commercial truck shipping docks, including somecontainerized cargo docks. In addition, the RDC can lower its top deckto a height of just 35.6 cm above ground level, which improves itscornering stability, passenger de-boarding and reachable height forusers who are removing parcels from its Locker Bin.

The RDC and EPC both have miniaturized modular on-board autonomousnavigation and positioning hardware that couple to their rearwheelmotors and steering to enable these carts to precisely align withdock locations where loading and off-loading are to occur. The precisionpositioning system in the EPC and RDC operates with a miniatureelectronic sensor suite similar to that in the SkyQart.

The RDC has a nominal gross vehicle weight of ≤907.2 kg.

The SBPs are held in place on the RDC by latching solenoid pins similarto those used to hold the EPC to the SkyQart cabin floor.

A special, alternative embodiment of the RDC can handle three SBPs atonce, which would comprise a 435.4 kg payload, by having its surfacedeck outfitted with both a top and bottom 205.74 cm length of heavy-dutydrawer slide. The height of the RDC's surface deck can be autonomouslyadjusted by the cart's scissor-jack to match the height needed toon-load or off-load SBPs to either its top or bottom drawer slide,whether they be charged or discharged. This special alternativeembodiment of the RDC can thereby serve as a shuttle for moving SBPsaround the dock, charging station or aircraft parking area. The heightof the SkyNest dock and that of the cabin floor of the SkyQart's AFPmust both be 47 cm in order for this special alternative embodiment RDCto engage as a shuttle.

The dock at the SkyNest can provide on its surface a path for the EPCback up to exit out of the rear hatch of a SkyQart and then to traverseto the opposite side of the dock where it can back-up onto the surfacedeck of a waiting RDC and pin-latch into place. This RDC can then departthe SkyNest with that payload-laden EPC to perform the last-mile home orcommercial delivery of that payload.

The RDC uses a scissor jack to raise and lower its top deck to match theheight of the dock that is in use. Each blade of the scissor jack hasnominally 159.18 cm between its end axles. The aft axles of each bladeeach hold a pair of hard polyurethane rollers that can tolerate theheavy loads involved. The battery pack-receiving tray under the top deckis for carrying SBPs and it is nominally 205.74 cm long, which allows itto carry two SBPs end-to-end, i.e. in tandem. The RDC's surface deck canbe lowered to a minimum height above ground of 35.6 cm and this heightdetermines the minimum height for off-loading EPCs at deliverydestinations other than SkyNests. A specially contoured standardizedramp can enable the EPC to be off-loaded from the surface deck of theRDC and onto ground or street level without scraping the EPC'sundersurfaces on the ramp. This standardized ramp must have gradual andcompatible contours in order to facilitate this task. The top edge ofthis nominal embodiment of the off-loading ramp for the RDC is 35.6 cmhigh, and the ramp is 343.4 cm long and 1.22 m wide. The ramp's surfaceis curved on an 838 cm radius with a symmetrical inflection in thatcurve in order to smoothly transition the EPC onto the ground or streetlevel. This nominal ramp is utilized at residential and other locationswhere off-loading of an EPC to the ground level needs to take place andwhere a dock with the standard specifications of a standard SkyNest isnot available. To utilize this special ramp, the scissor jack of the RDCmust be fully collapsed into the full-down position, which lowers theRDC's top surface to a height just 35.6 cm above the street level.

Alternatively, passengers riding an EPC atop an RDC may, when theirdestination is reached, simply unbuckle their seat harnesses and stepoff of the RDC and walk away. RDCs whose EPC carries a Locker Bin withmultiple digitally locked lockers can either off-load that EPC at amanned distribution center, or the RDC can travel to each of the severaldestinations assigned to individual users of its lockers and notify eachuser to retrieve their package using their digital lockbox code when theRDC is parked outside their location.

The RDC must use a very compact, low-height front suspension in order tofit under the loading dock.

The width of the RDC must be less than 1.22 m in order for it to qualifyas a neighborhood electric vehicle and thereby be accorded use ofbicycle lanes in some states.

The street-side of a SkyNest dock facility is typically provided withspecial RDC cart service bays that are called cart docking stations andthat have compatible heavy-duty drawer slides under the dock surface,which surface is at the standard height of 47 cm so that the RDC can useits scissor jack and precision positioning system to align the surfacedeck of the RDC with that of the dock surface and then load and unloadEPCs and SBPs. In alternative but less common embodiments, the cartdocking stations may be adjacent to the aircraft docking stations on thesame side of the dock facility as the pavement for the taxiways. To helpmaintain the alignment of the RDC with the cart docking station, thedock edge has two solenoid-actuated pins of 6.35 mm diameter that canprotrude from the dock to engage in two pin receptacle holes in the edgeof the front of the surface deck of the RDC. These pins and holes areboth 81.28 cm apart and symmetrically straddle the center point of theRDC and the RDC cart docking station.

The standard RDC has 30.5 cm outside diameter pneumatic tires with 1.9cm diameter axle size and each tire is rated for a 202 kg load²⁰. The30.5 cm tire diameter enables the wheelmotors on the RDC to operate atrelatively higher RPM, and the pneumatic character of the tires helpsthe RDC operate on rough surfaces at its speed limit of 40.2 km/hr.

In most U.S. states, the RDC is required to have headlights, taillights,stoplights, turn signals, horn, fenders, windshield, wipers and aretractable rain roof in order to operate on city streets.

The swappable rechargeable RDC special battery pack is located insidethe bottom of the frame of the RDC's steel chassis and has nominaldimensions of 5.08 cm H×50.8 cm W×50.8 cm L with a nominal capacity of12.8 kWh and a nominal weight of 32 kg. This RDC battery can also becharged during docking through the cart docking station's DCfast-charging port that automatically connects to the RDC's DCfast-charging port on the forward edge of the RDC when it is preciselydocked. The RDC battery pack is sufficient for a range of at least 32km.

The scissor jack on the RDC is driven by dual electric orelectro-mechanical linear actuators.

The RDC has a low-profile front suspension in order that the height ofits surface deck can as low as possible above street level.

The outer dimensions of the RDC are 2.44 m in length×116.8 cm wide,becoming 1.22 m wide when the retractable rain roof is attached. The RDChas a nominal 210.5 cm wheelbase.

The top speed of the RDC is limited to 40.2 km/hr in order to qualify itas a Neighborhood Electric Vehicle (NEV).

The RDC chassis has four separate solenoid operated latch pins of 6.35mm diameter. The gap from these solenoids to the sidewall of an EPC thatis aboard the RDC is uniformly 3.81 mm. The longitudinal spacing of thelatch pins on the RDC is the same standard 77.5 cm between centers asthe longitudinal spacing between latch pins that are used on the sidesof the AFP of the SkyQart.

Both the floor surface of the RDC and that of the SkyQart cabin provideshallow grooves that match the track width dimension of the EPC to helpkeep its wheels aligned during loading. Like the EPC, the RDC isequipped with a precision positioning system that includesline-following software that enables it to exactly align with theSkyQart cabin or a cart docking station, respectively. Thisline-following software can align with and precisely move the EPC or RDCalong a line projected onto the dock surface or pavement surface,respectively. A continuous guideline with sharp edges that emanatesoutward onto the pavement surface from the dock edge at the center ofeach docking station has a fixed width in the range of 3.175 mm to 12.7mm. This line is either painted, taped on or projected by laser, and isof a color that sharply contrasts with that of the pavement. This lineprovides an alignment path to guide the line-following software that ison-board the RDC that intends to move precisely to the said center ofsaid docking station. Both the SkyQart and the dock itself are capableof projecting such laser lines onto those surfaces so that the laserline leads the surface cart to the exact center of the floorboard of theSkyQart or the exact center of the docking station, respectively. Suchexact alignment enables the latching pins of the solenoid-actuatedpin-latching system to engage and pin-latch these vehicles and itprevents collisions between the carts and the solenoid bodies or pins.

If for any reason a SkyQart is unable to taxi to the dock, the RDC candrive onto the SkyNest pavement to reach that remote stranded SkyQart,use its precision positioning system and line-following software to dockwith it, and can rescue its EPC and passengers. It can also swap thatremote SkyQart's spent battery pack for a fresh one if necessary.

Dock Standards and Battery Swapping Standards

The Dock Standards and Battery Swapping Standards are two componentsthat are important to this invention. A QUAD SkyNest must usestandardized dimensions and facilities in order to achieve high capacityand to expedite deliveries. The QUAD dock height standard is 47 cm abovethe pavement on which the SkyQart parks. This 47 cm dimension matchesthe cabin floor height of the SkyQart, which is set low in order tocreate a low center of gravity for the vehicle and to confer maximumpassenger headroom in the cabin. This 47 cm dimension also matches theheight of the surface deck of the RDC during its docking operations. Thestairs from the SkyNest's perimeter sidewalk that lead up to the docksurface are nominally 1.83 m wide and consist of three steps, eachhaving a rise of 15.66 cm and 35.6 cm of horizontal tread run. Theseprovide the 47 cm of rise that is needed. In addition, there are severalAmerican Disabilities Act (ADA) compliant ramps that provide therequisite 1:14 standard rise from the street/sidewalk up to the SkyNestdock height of 47 cm. These ramps each have two stages. They use a 152.4cm×182.9 cm level landing platform as an intermediate stage afteraccomplishing the first 25.4 cm of the 47 cm rise with a pair of rampsthat are 355.6 cm long. The final 21.6 cm of rise is accomplished by thesecond stage of the ramp, which runs perpendicular to the dock.

The dock thickness at its outer edge where it interfaces with theSkyQart or RDC is nominally 28.58 mm. This edge contains thetransponding alignment target for the precision positioning systemlasers of the SkyQart and RDC, as well as the two 6.35 mm diametersolenoid-actuated tapered pins that protrude 19.05 mm from the edgesurface of the dock to mechanically maintain alignment of the docksurface with the surface deck of the SkyQart and RDC during loading andoff-loading of the EPC. These dock pins are 81.28 cm apart and theysymmetrically straddle the center point of the docking station. Duringdocking, these dock pins engage into equally spaced 6.86 mm diameterreceptacle holes in the edge of the surface deck of either the SkyQartor RDC. There is a separate alignment target for the precisionpositioning system at each mating center along the dock edge and thesetargets are equally spaced horizontally at intervals of 4.572 m.

The nominal interoperable 4.572 m intervals for docking allow thetightly spaced side-by-side docking of SkyQarts. The docking center isthat portion of the dock that is specially equipped to off-load andon-load both EPCs and SBPs. There is a recess underneath the dockingcenter between the dock's support pillars to allow the SkyQart's mainlanding gear to roll under the dock. To avoid the complexity, safety,and reliability problems of folding wings, there are two differentversions of the standard SkyQart (SkyQart I and SkyQart II) and thesecan be parked at the dock with overlapping wingtips. This reduces therequired space between their docking station to just 9.144 m. Oneversion of the standard SkyQart, named SkyQart I, has each of itswingtips tipped slightly upward at a nominal dihedral angle of 8.84°.The other version of the standard SkyQart, SkyQart II, has each of itswingtips tipped slightly downward at a nominal anhedral angle of 11.86°.A third version of the SkyQart is the dual-AFP version, or SkyQart III,which has each of its wingtips tipped slightly upward at a nominaldihedral angle of 9.58θ in order to enable it to overlap at each of itswingtips with the anhedral version, the SkyQart II. The SkyQart IIIversion has a distance of 4.572 m between the centers of its AFPs, sothat it can align and dock at any two adjacent aircraft docking stationsin order to load and unload each of its AFPs simultaneously. If aSkyQart III docks next to a SkyQart II, it can overlap its wingtips andthereby dock with a separation of just 9.14 m between its nose-tire andthat of the adjacent SkyQart II. If two identical standard SkyQarts dockside-by-side, their wingtips cannot overlap and therefore they must parkat aircraft docking stations that are 13.715 m apart. A computerizeddock utilization program directs incoming SkyQarts of the various typesto park at a compatible aircraft docking station that ensures bestoverlaps so as to maximum system capacity. Because of their differentwingtip angles, the SkyQart I and SkyQart II will have slightlydifferent flying qualities, particularly with regard to spiral stabilityand Dutch roll. However, it is anticipated that this will not be asignificant problem because of two factors: 1) the high wing design ofthese aircraft and 2) the use of autonomous flight and thrust controlswith negligible latency that can anticipate and compensate for theseinstabilities.

Battery swapping of the standard swappable battery pack (SBP) is anecessity because the SkyQarts will be operating on a nearly continuousduty cycle consisting of short-range flights. The swapping must beaccomplished precisely, reliably and rapidly without risk of damage tovehicle, dock or SBP. It must not delay or impede system capacity. Itmust be resilient in its operations, with multiple loading, unloadingand charging stations operating in parallel, including, during powerfailures, an allowance for manually operated swapping if necessary.These requirements favor using sturdy extensible drawer slides formoving the battery packs during the initial interface with the SkyQartand RDC in the exchange process. Ball-bearing extensible suspensiondrawer slides that are strong, affordable, fast, precise, replaceable,manual, and of a consistent standard in size are to be used.McMaster-Carr offers such drawer slides as 101.6 cm long slide railscapable of supporting 199.6 kg and whose cross-section is 7.62 cm talland 19.05 mm wide. These are adopted as the standard in this embodimentof QUAD facilities and vehicles for moving the standard swappablebattery pack (SBP) of 8.89 cm H×66.0 cm W×101.6 cm L and that weighs145.15 kg as used in SkyQarts I, II and III. Each battery pack is aself-contained package that includes a sturdy outer shell, internalseptae and cooling passages, a battery management system, externalelectrodes for both power and the battery management system/charginginterface and side rails that are compatible with the standardizedheavy-duty drawer slides described herein. Battery packs are rated at astandard 600 volts DC. Alternative embodiments of the SBP may be ratedas low as 400 volts and as high as 800 volts. The standard SBP capacityis 58 kWh (with a range in alternative embodiments of 30 to 80 kWh), butthis will vary between battery packs of differing vintages as energystorage technologies improve. This 58 kWh energy source may besupplemented in some embodiments of the SkyQarts by the addition of asuper-capacitor either inside the SBP or inside the SkyQart's AFP. Thesuper-capacitor's purpose is to augment the capability of the battery torapidly supply the large amounts of electrical current needed for thebrief periods of high power demanded for take-off acceleration.

At the high capacity SkyNest, the facilities at the dock will haverobotic stacking of battery packs onto a battery charging rack that isequipped with high capacity DC charging connections. At each aircraftdocking station, these battery charging racks will be located under thedock on either side of a central battery swapping robot. There will alsobe a single high capacity DC fast-charging port located on the externalsurface of the edge of the dock at each aircraft docking station so asto mate with the DC fast-charging port that is located on the lower faceof the SkyQart's rear hatch opening.

The standard swappable battery pack (SBP) is retained in the SkyQart bydual latches that can be released by either operation of an electricsolenoid-actuated pin or by manual operation.

The moving of the SBP at the dock can be accomplished by a robotic armthat grips and releases the battery pack using suction cups or by anelectromagnet grip face applied to a ferrous metal surface on the pack.At relatively less busy, lower capacity SkyNests, the battery swappingcan be simpler and less expensive, with manual transfer of SBPs from thedocked SkyQart onto the drawer slides in the space just under thesurface of the dock and thence on a continuum of said drawer slidesacross the full width of the dock to a waiting RDC at the opposite sideof the dock that can receive and then deliver the SBP(s) to a nearbycharging station. Alternatively, an RDC can use its precisionpositioning system to approach and align with the rear hatch opening ofa stranded SkyQart that is parked on the parking ramp of the SkyNest andexchange its SBP directly without a dock. An RDC can also deliver afreshly charged battery to the drawer slide under the dock so that itcan be inserted and latched into a waiting SkyQart.

High capacity SkyNest docks can use a specialized central robot arm toaccomplish fast and precise movement of the SBPs to a battery chargingrack that recharges SBPs under the dock. The articulated specializedcentral robot arm can rapidly move in complex 3D paths, to unload andload freshly charged SBPs to and from a battery charging rack. Suchrobotic arms grip the SBP without crushing it by using either vacuumcups or an electro-magnetic under-cradle to lift the SBP. There must bean alternative method to exchange the SBP in case the robot arm iswithout power or is inoperative. The under-dock central robot arm willhave the ability to be moved out of the way when it is inoperable. Aslower, manual handling option for SBPs is made possible by having twoinsertable 205.7 cm long drawer slide segments that can be attached andaligned with the drawer slide gap on the underside of the dock to createa continuous drawer slide path for moving SBPs from a docked SkyQartacross the full dock width distance of 7.47 m to the far opposite sideof the dock where an RDC can on-load them in order to transport them toa remote charging station. For general aviation airports and start-uplocations for QUAD, these manual SBP swapping methods may precede theinstallation of high capacity robotic swapping with battery chargingrack. A specialized double-decker RDC whose top surface is equipped witha second set of SBP drawer slides that can be lowered by the RDC'sscissor jack to exactly align with those of the SkyQart for off-loadingSBPs from docked SkyQarts provides an alternative method of loading andoff-loading SBPs. However, this double-decker RDC method of off-loadingSBPs is slower than the fully automatic robotic system. By use of itsscissor jack and compatible precision positioning system, the doubledecker RDC with its upper and lower set of drawer slides can provide aversatile loading/off-loading option for SBPs on both the docked SkyQartas well as for the SkyQart that is stranded or immobilized on theparking ramp.

The nominal SBP will weigh 145.15 kg. Its weight is likely to decreaseas future battery energy densities improve. The SBP's kWh capacity willalso rise as future energy densities improve with technologic progress,which will increase the SkyQart's range and decrease the number of SBPswaps needed per day. Alternatively, the standard battery pack for QUADmay have different dimensions, voltages and energy capacities as long asthose standards fit the standards used for drawer slide spacing andelectrical systems in the QUAD vehicles, dock and storage racks. Ifaverage trip length for the QUAD system is 48.3 km, then batteryswapping will likely only be needed every other flight or even every3^(rd) flight. Swapping takes time and costs money. Ideally, at thebusiest hubs, swapping should be accomplished consistently in less than20 seconds. That leaves 10 seconds for removal and 10 seconds forinsertion of the fully charged SBP. With fast robot arms, swapping couldbe accomplished in as little as 5 seconds for removal and 5 seconds forinsertion, but that would be unlikely to be needed in the first fewyears of operation the QUAD system. After the 10-second removal and10-second insertion are accomplished, there will be another timeinterval of at least 20 more seconds before the next SkyQart arrives inposition at the dock. If that SkyQart does not need a battery swap, thenanother 20 seconds will pass before it departs the dock with its newlyboarded passengers and yet another 20 seconds will pass before the3^(rd) SkyQart arrives ready for a battery swap at the dock. An outlineof this sequence of battery swapping for SkyQarts (SQs) is shown inTable 4.

TABLE 4 Time Event Battery needed 0:00 SQ #1 arrives at dock 0:20Battery swap complete 1 0:40 SQ #1 leaves, SQ #2 arrives 0:60 No swap,passenger boarding only 1:20 SQ #2 leaves, SQ #3 arrives 1:40 Batteryswap complete 1 2:00 SQ #3 leaves, SQ #4 arrives 2:20 No swap, passengerswap only 2:40 SQ #4 leaves, SQ #5 arrives 3:00 Battery swap complete 13:20 SQ #5 leaves, SQ #6 arrives

The ratio in this modeling of battery swapping is three swaps to everytwo no-swaps and this ratio consumes three freshly charged batteriesevery three minutes and 20 seconds. This is equivalent to requiring onefreshly charged SBP every 66.6 seconds. From extant technologies, it canbe presumed that an SBP can be fast-charged to more than 80% capacity injust 20 minutes. Therefore a 20-minute supply of batteries will consumesix of the above 3:20 cycles and must therefore have 3×6=18 freshlycharged battery packs to be on hand for each aircraft docking station atthe high capacity SkyNest. This means that, at peak operating capacity,each of the eighteen battery packs should complete its dock cycle ofremoval to recharge to re-insertion in just over 20 minutes. The rapidconsumption of an SBP every 66.6 seconds requires that the batterycharging rack at each docking space must have at least eighteenfast-charging outlets, each one capable of supplying about 100 kW ofcontinuous power. That will demand 18×100=1800 kW of continuous power ateach aircraft docking station at the high capacity SkyNest. That is morethan 2400 BHP of continuous power at each aircraft docking station. Withthe wide street adjacent to the SkyNest covered with solar panels thatextend over the dock area, at sunny high noon and with 30% efficiency,the solar panel array for the SkyNest can generate 2453 kW of power fromits nominal 8175 square meters of solar panels, which is sufficient tosupply the electricity needs of just one high capacity aircraft dockingstation. This solar capacity limitation indicates that the SkyNest musthave an additional source of grid electrical supply to supplement itsown solar panel array.

Each aircraft docking station can provide space for four batterycharging racks, two on either side of the robot arm. Each batterycharging rack has five slots arranged vertically. Each such slot canhold an SBP. The robot arm can insert an SBP into a slot in less than 10seconds. It can likewise remove an SBP from a slot in less than 10seconds. The four battery charging racks at an aircraft docking stationhave a combined capacity of holding and charging twenty SBPs. Each ofthe five slots in each battery charging rack has compatible hardware toDC fast-charge, monitor and cool an SBP. The battery charging racksthemselves are arranged as modules that can receive a spent SBP in anempty slot and supply a separate fully charged SBP from another of itsslots. The robot arm can grab the freshly charged SBP from a slot in theBCR and insert it into the docked SkyQart. The BCRs are mounted onsturdy 4-wheel carts in order to be movable and serviceable. A batterymanagement system, and charge monitoring system informs the robot aboutwhich slot is empty in the BCR and which slot can provide a fullycharged SBP.

Graph of Tolerable Jerk Rate on Take-Off

The rate at which acceleration increases during the take-off roll anddecreases during landing roll can only be as high as will be tolerableto the public fare-paying passenger. This graph depicts the range ofthose accelerations for take-off. The rise and fall of accelerationrates are called the jerk rates and they are used to model the 4Dtrajectories of the SkyQart in its standard operations at the SkyNest.Passenger-acceptable jerk rates are derived from the jerk rate limitsadopted by the industry for amusement park rides. The comfort limit forchanges in acceleration used by that industry is a jerk rate ofgenerally about 3.4 m/sec³ both in terms of increasing accelerations ordecreasing accelerations in both the vertical and fore-aft axes. Allmovements executed by vehicles in the QUAD system, including theSkyQart. EPC and RDC, and whether in accelerating or decelerating, willbe constrained to the extent possible to be at or below the jerk rate of±3.4 m/sec³ in the vertical and fore-aft directions. This constraintmodel for movement is herein named guided rate acceleration changeexecution or GRACE.

The Standard Battery Pack (SBP)

The standard battery pack SBP is an important component of thisinvention. It is used in every model of SkyQart and it has standardspecifications and interfaces that are chosen so that the SBP can behandled both manually and by robotic equipment. The shape of the SBP isdetermined by its need to fit into the belly of the AFP at a lowwaterline so as to lower the height of the center of gravity of theSkyQart. The container of the standard SBP has nominal interoperabledimensions of 8.89 cm H×66.04 cm W×101.6 cm L comprising thereby 59.65liters, which, at the energy per volume of 975 wh/liter currentlyclaimed by Tesla²¹ can provide a 58.16 kWh battery pack of 145.15 kgwith a density of 2.44 kg/liter. The nominal interoperable battery packweight of 145.15 kg will vary within a preferred range of 120-150 kgdepending upon the energy density of the battery and the desired range.The pack consists of a large number of cells that are wired together inseries to create a standard pack voltage of 600 volts. The conceivablerange of voltages is from 400 to 800 volts in alternative embodiments ofthe SBP, with a preferred range of 550-650 volts. The pack has itspositive and negative electrodes recessed slightly below the forwardsurface of its outer case. When the SBP is inserted into the extensibledrawer slides in the belly of the SkyQart, these electrodes make firmand broad contact with corresponding spring-loaded electrodes in theforward belly of the SkyQart. The forward surface of the SBP includes acentral circular grommeted orifice for connecting to the SBP's batterymanagement system, which monitors the its capacity, temperature andcharging status. In some embodiments, the forward surface of the SBPalso includes two cooling ports, one port and one starboard, thatconnect the SBP's internal cooling channels to the SkyQart's supply ofcooling air or liquid coolant. These cooling ports are likely to not beneeded on future SBPs that have greater temperature tolerance andperformance as battery chemistries continue to improve. The outercontainer of the SBP is nominally a 0.406 mm thick stainless-steelsheetmetal case with a honeycomb pattern of internal structural supportsbonded to its inner surfaces so as to stiffen it for handling. Thismetal container serves to confine out-gassing or smoke emissions as wellas acting as a Faraday cage and RFI filter. The rear surface of theouter container has a midline opening that serves as a smoke vent incase of smoke emissions. This smoke vent mates to a short midlinestainless steel air duct in the rear hatch of the AFP that provides anexternal exit on the midline belly of the SkyQart. The bottom surface ofthe SBP's stainless steel container includes a ferrous steel plate thatfacilitates the ability of the robot arm to firmly grip the SBP whenmoving it. Firmly attached to each of the long 8.9 cm tall sidewalls ofthe SBP's container are the male component of the 1.9 cm wide heavy dutydrawer slides that mate with the female component of those drawer slidesthat is rigidly attached both to the side walls of the batterycompartment in the belly of each SkyQart as well as to the sides of thebattery swapping drawer slides under the dock and the drawer slides onan RDC.

Crash Cushion

The crash cushion is an important component to this invention. Itenables the concept and process of safely protecting SkyQarts andpassengers in the event of a loss of control on the pavement. The crashcushion is the component comprised of a specially designed cart that canjoin with other carts to form a moveable train of carts placed at theend of the SkyNest's active pavement in order to safely bring to a stopan out-of-control SkyQart. The relatively low speeds and light weightsof SkyQarts and their consistent and precise use of short runways makethis concept and process viable. As an affordable, moveable, cushionedcollision barrier, the crash cushion can provide a safe and controlleddeceleration to full stop of the SkyQart from speed as high as 30 m/sec.By safely halting the motion of an out-of-control SkyQart, the crashcushion can ensure that it stays within the limited boundaries of theSkyNest. The nominal embodiment of the crash cushion as a system iscomprised of a modular, impact-absorbing hybrid cushioning systemmounted on a heavy, moveable crash cushion cart that is nominally 4.88 min length. Each cart has four tires located at its four corners with anominal 139.7 cm track width and a nominal 365.76 cm wheelbase. Eachtire is nominally 25.4 cm wide and 40.6 cm in diameter. The two fronttires of each crash cushion cart are free to swivel 360° on casters inorder to allow positioning of the carts. When four such carts are joinedtogether with large caliber elastic bungee bands, they form a barrierwall that is nominally 19.5 m long that can be positioned on thepavement surface at the end of the active SkyNest runway to provide acollision barrier function. When so positioned, each crash cushion cartcan extend a pair of hinged reinforced steel plates downward from therear face of its rear vertical wall to form stabilizing gusseted footpads on the pavement surface. Each plate has a large rubber footpad onits under surface. Each of these steel plates can be secured in its downposition by a 12.7 mm bolt to apply the rubber footpad onto the pavementsurface below the cart in order to broaden the cart's base and help itresist it toppling during a collision. When the crash cushion carts arebeing re-located on the pavement, these hinged steel plates aretemporarily retracted upward and secured to the rear face of the rearvertical wall of the crash cushion cart. The structural base of eachnominal crash cushion cart is a stiff steel ladder frame that isnominally 17.8 cm tall. This ladder frame can be filled with either sandor water or both in order to obtain the desired mass for the crashcushion cart. The rear (non-impact) edge of the ladder frame is attachedto a hollow steel vertical rear wall of nominally 487.7 cm L×226.1 cmH×30.5 cm W that is welded along its bottom edge to the ladder frame.These bottom welds are strengthened by welded steel triangular gussets.This vertical rear wall supports the large airbag cushioning device onthe crash cushion cart. This vertical rear wall is, in turn, buttressedon its backside by the two large retractable steel plates that providethe stabilizing gusseted foot pads for each crash cushion cart. Toabsorb the initial impact of the nosewheel of the SkyQart, a sloped rampmade of a steel plate extends from the impact side of the cart's ladderframe outward for about 0.915 m underneath its large memory foam beanbagcushion and onto the pavement at ground level. This sloped ramp spansthe entire 4.88 m on the impact side of the crash cushion cart and ishinged where it joins with the cart's ladder frame so that it can belifted up off of the pavement during re-location of a crash cushioncart. This shallow-sloped full-length ramp is intended to allow theinitial impact of the SkyQart's nosewheel and landing gear to roll upthis sloped ramp as it compresses the soft memory foam beanbag cushionand thereby avoid striking a blunt edge of the thick ladder frame in thefirst 0.915 m of impact absorption. This ramp also serves to support thememory foam beanbag cushion as a wall, which is also suspended from thenominal 5.08 cm diameter frangible plastic masts on each end of thecart. There are two such masts and they are attached at each end of theladder frame 86.4 cm away from the impact surface of the memory foambeanbag cushions so that there will be nominally 86.4 cm of compressionbefore the impacting vehicle reaches these frangible masts.

Each junction between the joined crash cushion carts on their impactside is covered with a 0.254 mm thick flexible load-spreadingpolyethylene terephthalate (PET) tarp whose tensile strength is 55 Mpaand whose peripheral edges are secured with aramid fiber straps to thebeanbags on either side of said junctions. For the SkyNests I, II andIII, which have fixed headings of their pavement runways, the crashcushion carts can be permanently positioned at each end of the runwaywith their braced footpads on the pavement. For SkyNests IV and SkyNestsV which have selectable variable headings according to the current windconditions, the carts can be moved by towing them individually intoposition at the end of the active pavement and joining them into a trainof carts. The hybrid cushioning system on the crash cushion, which ispart memory foam beanbag cushion and part large airbag, provides aninelastic collision in which the SkyQart's kinetic energy on impact isgradually converted into a combination of heat, material deformation,movement and friction. The details of these processes are calculatedherein for this embodiment of the crash cushion. This embodiment isdesigned and modeled as a crash cushion that can arrest the motion of aSkyQart I & II or a SkyQart III from a groundspeed of 20 m/sec. Thisimpact speed of 20 m/sec is chosen because the nominal take-off andlanding airspeed of the SkyQart is 24 m/sec and there is nearly alwayssome headwind or rolling friction to reduce that to a groundspeed ofabout 20 m/sec as the nominal impact speed. This design model of a crashcushion is one of several possible embodiments in terms of crash cushionsize, weight and materials, all predicated on the same concept andprocess. This model presumes that the SkyQart's autonomous control hasapplied neither thrust nor braking at the time of the SkyQart's impactwith the crash cushion, making the SkyQart essentially a ballisticprojectile for the purposes of calculation.

The analysis of the collision of a SkyQart with the barrier cart knownas a crash cushion can be solved using the kinematic equations, theconservation of momentum equations and impulse analysis. This collisionis inelastic because it has negligible re-bound of the SkyQart afterimpact. For the calculations of the collision presented herein, an 846kg SkyQart I or II is presumed, although the nominal interoperableSkyQart weight is 857 kg. The SkyQart has irregularly shaped forwardsurfaces that upon impact, will gradually come to rest on the stationarycrash cushion cart. The majority of the SkyQart's kinetic energy getsabsorbed and dissipated into the cushioning materials on the heaviercrash cushion. The mass of the crash cushion cart is chosen so that aknown impact force will cause a short and harmless skid of the crashcushion cart. The mass of the crash cushion cart and the impact velocityof the SkyQart will mainly control the length of the skid²². Thecomplete analysis of such a collision involves additional variables(beyond the weights, speeds and coefficient of friction) that are beyondthe simplified calculations here. These additional variables include theunknown deformation of the nose of the SkyQart's AFP, the heating of thecushioning materials, the friction of sliding of the surfaces of thebeanbag on the forward parts of the SkyQart and other nearlyinstantaneous factors. Nevertheless, the method of analysis applied hereassumes average forces and constant acceleration with the expectationthat the dynamics of these unknown variables will be of relatively smallmagnitude. The crash cushion barrier cart is 4.88 m in length and sitson rubber tires that can skid with a known coefficient of friction onpavement. There are two functions of the crash cushion cart: 1) theenergy of the SkyQart's impact must be dissipated in a gradual enoughfashion and over a sufficient time and distance as to ensure that thepassengers inside the SkyQart are exposed to tolerable levels of G; and2) to the extent possible, the impact force must be distributed andspread evenly onto the leading surfaces of the SkyQart such that itlikewise suffers minimal damage. This latter function demands that theinitial impact of the SkyQart with the crash cushion cart be one inwhich its cushioning materials conform to and envelop the irregularlyshaped forward surfaces of the SkyQart to thereby provide aload-spreading function. Within milliseconds after impact, the cushionsof the crash cushion cart must not only conform to these forwardsurfaces of the SkyQart, they must then themselves progressivelycompress the other cushioning materials on the crash cushion cart. Asthis happens and the force of impact is progressively transferred to thestationary crash cushion cart, until said force reaches the point atwhich the crash cushion cart is designed to break loose and skid someshort distance to a full stop to dissipate the remaining energy of theimpact to zero. The relevant variables in analyzing this inelasticcollision are the mass of the SkyQart, its initial impact speed, themass of the crash cushion cart, the coefficient of friction of the skidof rubber tires and rubber footpads on pavement, (−μ_(f)), the ‘springrate’ (resistance to deflection) of the cushioning materials and theircoefficients of restitution. The cushioning materials are selected so asto make the crash cushion dissipate the kinetic energy of the SkyQartacross a distance, “d₁”, so as to result in a tolerable level of G. Fromthe information in Table 5, below, a total deceleration distance of 2.6m is selected as ideal. That 2.6 m is comprised of 1.5 m of compressionof crash cushion cushioning materials and an additional 1.1 m of skiddistance on the pavement of the combined SkyQart/crash cushion cart. Thecushioning materials consist of a beanbag filled with small pieces ofmemory foam and a large airbag. The tailoring of the cushioning of thebeanbag is by the amount and density of the memory foam pieces usedinside it. The tailoring of the cushioning of the large air bag is bythe sizing of its air vents so as to control the air bag's resistance tocompression such that the velocity of the SkyQart would be substantiallyreduced on the crash cushion cart over a total compression distance d₁of 1.5 m. The proposed material to provide the both the cushioning andshape-conforming functions is made of large memory foam beanbags,stitched together and suspended vertically to form a wall whose heightis tall enough to block the SkyQart's motion. An example of such amemory foam beanbag is here²³. Its specifications are as follows:weight, 41.7 kg for each 2.44 m L×2.44 m W×86.4 cm H. Combining two ofthese beanbags by stitching the beanbags together can form a wall thatis 2.44 m tall and 4.88 m long with 86.4 cm depth with a total weight of83.5 kg, according to The Bigairbag company²⁴. It can provide acustomizable inflatable airbag that has internal baffles, external ventwindows, internal blowers and an anchoring system. Such a large air bagcan be engineered to provide a compression pillow on the backside of thecrash cushion memory foam beanbag wall with sufficient strength andresistance to compression by the impact of a SkyQart that it willdeliver the calculated performance in energy absorption. The analysis ofthis inelastic collision is predicated on there being no external forces(e.g. propulsion or braking) on the SkyQart or crash cushion so that thelaw of conservation of momentum can be applied. That law basically saysthat if a mass m₁ traveling at velocity v₁ strikes and sticks to astationary mass m₂ whose velocity is v₂=0 on a frictionless surface,then the final velocity, v_(f) of the combined masses can be found bythe formula:

m₁*v₁+m₂*v₂=v_(f)*(m₁+m₂) is the formula for computing conservation ofmomentum. The collision of the SkyQart with the crash cushion is anisolated system because any frictional force during the brief collisionperiod is presumed to be of insignificant magnitude. Within the impulsecomputation of force times time, the momentum of this collision will beconserved. After the collision with the stationary crash cushion cart,the frictional force and application of Newton's second law andkinematic equations can be used to find the distance that the combinedSkyQart/crash cushion cart will skid. From the instant of impact, theSkyQart progressively decelerates into the cushions of the crash cushionas the resisting force of those cushions is progressively increasing.For simplicity, we here analyze the collision in metric units only, andwe assume that the SkyQart is not losing energy due to rolling frictionor braking, nor is it gaining energy by propulsion. Rather we assumethat at the instant of impact, the SkyQart is a passive ballisticprojectile with zero thrust and with the bottom of its tires at a heightof about 12.7 mm off the pavement. After it compresses the memory foambeanbag and large airbag cushions on the crash cushion by 1.5 m, theSkyQart becomes embedded into the crash cushion cart and the combinedSkyQart/crash cushion cart begins to move as a unit in its skid alongthe pavement. The cushioning materials are designed so that the cushioncompression distance d₁ will be 1.5 m because that is a lengthsufficient to result in tolerable G's experienced by passengers as theSkyQart is slowed from it 20 m/sec impact speed. The initial skiddingspeed of the combined SkyQart/crash cushion cart can be calculated. Theskid of the combined masses of the SkyQart/crash cushion cart continuesthe positive horizontal movement of the SkyQart across the skid distanceof d₂, which is 1.1 meters. The total distance traveled by the SkyQartfrom impact to full rest is 2.6 meters.

Autonomous Control System

The autonomous control system of the SkyQart is an important componentto this invention. The autonomous control system and its suite ofmultiple sensors for autonomous navigation, aerial agility, ‘polite’,sense and avoid traffic and obstacle separation in nearly all-weatherconditions, functioning at a fully independent level of autonomy, willnot be available for the QUAD system in its initial operations. Thismeans that lesser levels of autonomy, including optionally pilotedaircraft (OPA) with human pilots, and/or remotely piloted aircraft usingbunker pilots, will be employed in the initial phases of QUADimplementation. These will be included by inference in this invention.The rapid progress in driverless vehicle technology is expected to sooninform and produce affordable ‘drop-in’ autonomous control modules thatcan be adapted for use in the QUAD system, pending their certificationby FAA. Such autonomous flight controls need not be present on the firstiterations of the SkyQarts in order for it to be covered under thispatent. However, autonomous flight controls, when available, mustinclude, at minimum, appropriate servo-motor control of the positions ofailerons, rudder, flaps and elevator in order to enable safe, controlledflight and use of the fast flaps system. Similar autonomous control ofspoilers, propeller thrust or drag, active landing gear, wheelmotors,rear hatch, pin-latching and battery swapping will be needed for thenominal embodiments of the SkyQart to operate at SkyNests as describedherein. The operation of these several autonomous control functions willcomprise the autonomous control system. The SkyQart's on-boardautonomous control system will integrate with a computerized networkedsituational awareness system and a precision positioning system at eachSkyNest that, along with other air and surface vehicle guidance systems,will coordinate and control the sequencing, movements (includingtake-off, landing and taxiing) and positioning of SkyQarts, EPCs andRDCs on SkyNest surfaces and dock areas. This sequencing, movement andpositioning will in all cases possible be performed by the autonomouscontrol system with negligible control latency and with GRACE. Theautonomous control system will require a diverse suite of multiplesensors that provide a variety of signals and data to the centralcontrol software program that performs sensor fusion on-board theSkyQart. Precision Positioning System (PPS)

The precision positioning system is an important component to thisinvention. It is the concept and process by which the various types ofcarts of the QUAD system autonomously dock with each other and with theSkyNest dock to enable QUAD's high capacity for moving people and goods.The precision positioning system relies upon sophisticated electronicvehicle guidance devices that use multiple miniature electronic sensorsin sequenced sensor fusion to enable docking accuracy to be nominallywithin +2.0 mm. There are several types of docking in the QUAD systemfor which the precision positioning system is important. In every type,there is an approaching vehicle and a stationary dock or other vehicle.The types of approach include SkyQart to dock. EPC to SkyQart, EPC toRDC, RDC to SkyQart, RDC to SkyNest dock and RDC to commercial truckdock or to a compatible off-loading ramp. The approach to the dock ismade in phases that are appropriate to the range and accuracy of thesensors involved. The nominal SkyQart's approach to the dock begins witha phase that is an initial gross approach to the dock using differentialGPS and inertial navigation system (INS) to guide the main landing gearwheelmotors to taxi to and park in a position about 13.7 m from thedock. This parking position is preparatory to the SkyQart backing intoward the target aircraft docking station, which must be accomplishedin just 10 seconds. This initial gross approach phase is followed by amore accurate phase in which the SkyQart backs up toward the aircraftdocking station using line following software to command its active mainlanding gear wheelmotors to follow a laser line on the pavement thatpoints directly to the target center of the aircraft docking station andguides the SkyQart to within about 1.83 m of it. The line followingsoftware is aided by a camera vision system that avoids obstacles. Thisphase, in turn, is rapidly and seamlessly followed by a 3rd phase inwhich proximity to the dock is determined by auto-focus technology. Thisauto-focus system may be either or both an infrared emitter type (whichcan function in the dark) or a passive vertical and horizontalauto-focusing CCD camera chip on the SkyQart that guides the wheelmotorsto steer the SkyQart toward a small, high-contrast alignmentcheckerboard target on the dock, bringing it to within about 15.24 cm ofthe dock. The 4^(th) and final alignment and docking phase isaccomplished as a two-step sequence using two sensor systems: 1) a pairof four convergent helium-neon (HeNe) laser beams, aimed at theirrespective transponder receiver plate on the dock, bring the SkyQart towithin 19.05 mm of the dock where the capacitive proximity sensors thenguide the final 19.05 mm of movement by which the two 6.35 mm diametertapered pins that protrude from the dock engage into the two horizontalpin alignment receptacle holes in the aft edge of the surface deck ofthe SkyQart. For redundancy and verification, the sensor types of theinitial docking phases continue to gang monitor and corroborate thealignment process that is being guided by the sensors in the laterdocking phases. The vertical alignment of the approaching vehicle withits target is accomplished by the active main landing gear in theSkyQart and by the scissor jack in the RDC, each of which are guided bythe sensors to maintain the correct vertical alignment. At theconclusion of the approach, the SkyQart must have aligned its surfacedeck (the cabin floor) and battery drawer slides with those of the dockso that the two 6.35 mm diameter tapered solenoid-activated pins areengaged into the two horizontal pin alignment holes in the aft face ofthe SkyQart's surface deck. The engagement of these pins maintains thenecessary alignment of the SkyQart to the dock. This combined parkingalignment technology enables the SkyQart to rapidly load and unloadEPCs, as well as automated connection of the SkyQart to the dock's DCfast-charging port. The standard dock thickness at its outer edge whereit interfaces with the SkyQart or RDC is 28.58 mm. This edge containsthe alignment target for the precision positioning system lasers of theSkyQart and RDC, as well as the two 6.35 mm diameter tapered pins thatprotrude 19.05 mm from the dock to mechanically maintain alignment ofthe dock surface with the floor height of the SkyQart and RDC duringloading and off-loading of the EPC. There are separate alignment targetsfor the precision positioning system at each aircraft docking stationalong the dock edge and these targets are equally spaced horizontally atintervals of 4.57 m. The RDC and EPC each have miniaturized modularon-board autonomous navigation and positioning hardware that couple totheir rear wheelmotors and steering to enable these carts to preciselyalign with docking stations where loading and off-loading are to occur.The precision positioning system in the EPC and RDC operates with asimilar miniature electronic sensor suite as that in the SkyQart. At thestreet side of the SkyNest dock, the RDC is provided with its ownspecially dimensioned cart docking station where it can align with thedock height of 47 cm using its precision positioning system. Theprecision positioning system on the RDC can steer the swiveling nosetires, and the RDC's steering is augmented by differential control ofits rear wheelmotors, each of which is nominally 3 kW and is driven by anominally 6 kWh, 15.4 kg battery pack. If for any reason a SkyQart isunable to taxi to the dock, the RDC can drive onto the SkyNest pavementramp or taxiway to reach and rescue a remote stranded SkyQart, using itsprecision positioning system and scissor jack to dock with it, andthereby rescue that SkyQart's laden EPC and SBP. It can also swap thatremote SkyQart's spent battery pack for a freshly charged one ifnecessary. An RDC can also deliver a freshly charged battery to thestreet side of the dock where the battery drawer slide under the dockcan receive it so that it can be slid on the drawer slides underneaththe dock across the full width of the dock to be pin-latched into adocked and waiting SkyQart at the opposite side of the dock. By use ofits scissor jack and compatible precision positioning system, the doubledecker RDC with its upper and lower set of drawer slides can provide aversatile loading/off-loading option for SBPs on both the docked SkyQartas well as for the SkyQart that is stranded or immobilized on theparking ramp. Each battery swapping station at a QUAD dock has a pair ofprecision positioning system transponder receiver plates mounted on theface of the dock on either side of the center point of the dock batteryswapping station. Each precision positioning system transponder receiverplate receives four convergent He—Ne laser beams from the emitters onthe aft face of the sidewalls of the SkyQart's rear hatch opening, andthe receiver plates process the information from those laser impingementpatterns into a wireless transmission back to that SkyQart to provideguide signals for the SkyQart's wheelmotors and active main landing gearto steer the SkyQart into the exact required horizontal and verticalalignment with the dock's battery swapping station. To help ensureprecise docking with the HeNe lasers, the precision positioning systemalso employs a combination of multiple other miniature electronicsensors in sensor fusion. Co-located on the dock face with the precisionpositioning system transponder receiver plates are two capacitiveproximity sensors for short-range positioning, which help guide theSkyQart to park exactly at the appropriate station at the dock with a 3Dprecision of ±2.0 mm. This guidance is assisted by the Active MainLanding Gear that is able to control and set the ride height of theSkyQart during its dock maneuvering. When the rear hatch is fully open,a SkyQart may be precisely positioned and aligned with the dockmanually. This can be accomplished by simple visual alignment of thefine-line markings on the SkyQart's rear floor centerline with thosefine lines on the dock surface at the center of the aircraft dockingstation. The manual docking of a SkyQart requires use of a nosewheeltowbar and a wireless remote control that is authorized to command theheight settings of the active main landing gear.

Wheelie Prevention System

A wheelie on take-off is prevented by a combination of components thatare configured to keep the nose tire on the pavement during theaggressive take-off acceleration of a SkyQart.

A downforce on the nose tire is produced by a propeller whose thrustaxis is at least 60 cm or more above the center of gravity of a SkyQart.A standard battery pack whose mass is located below the cabin floor ofthe axisymmetric fuselage pod lowers the SkyQart's center of gravity,which helps prevent a wheelie during take-off. An active main landinggear can help prevent a wheelie by positioning the main landing gear legat a lowered position at the moment of brake release so as to reduce thewing's angle of attack and create a downforce forward of the center ofgravity during the initial take-off roll. At the moment when theindicated airspeed becomes sufficient for lift-off, the active mainlanding gear can retract the main landing gear leg upward so as toincrease the fuselage pitch angle in order to suddenly increase thewing's angle of attack and lift and thereby induce lift-off. The wheelieprevention system includes a wing whose extended wing flaps duringtake-off produce a nose-down pitching moment that also helps to preventwheelies by keeping the nose tire on the pavement during take-off. Thelong wheelbase and the forward location of the SkyQart's center ofgravity along with a far forward location of the nose tire also help toprevent a wheelie. The forward center of gravity requires a horizontaltail coefficient large enough to induce a nose-up pitch attitude whenthe indicated airspeed becomes sufficient for lift-of. The autonomouscontrol system has a sensor for fuselage pitch angle that enables it toinstantly modulate the thrust of the main landing gear tires, the thrustof the propellers, the landing gear leg position and the wing flapposition in order to prevent a wheelie.

TABLE 7 Nomenclature Summary 3 D: three dimensional 4 D: athree-dimensional path along which each point has a specific clock time(0025) Above mean sea level, describing elevation or altitude on astandard day AFP: axisymmetric fuselage pod ANS: Acceptable Noise Spheree.g.: center of gravity CO2: carbon di-oxide, a greenhouse gas dBA:decibel level on the “A” weighted scale EPC: electric payload cart, adriverless cart that carries people or goods latched to its surfaceESTOL: extremely short take-off and landing FlyQUAD: the mobile devicesoftware application for reserving a flight in QUAD Faraday cage aroundbattery pack, to contain dangerous high voltage and radio interferenceG: the acceleration due to gravity at sea level on Earth, 9.81 m/sec²GPS: global positioning system Ground travel time, the total ofnon-airborne time during a trip using QUAD GRACE: Guided RateAcceleration Change Execution L_(den): level in dBA, day, evening andnight, a standard metric for noise measurement kg: kilogram unit of masskm/hr: kilometers per hour kWh: kilowatt-hour, unit of energy = 1000watts for one hour kW: kilowatt, unit of power = 1.34 horsepower lastmile: the final ground travel portion of a trip to reach a doorstepdestination Landing gear wheelmotor, an electric motor embedded inside alanding gear's wheel Minimum buffer zone, a separator between SkyNestsor SkyNest and community m: meter, metric unit of length, equivalent to3.2808 feet National Household Travel Survey, a reputable report ontransportation statistics Networked Situational Awareness, software thatcontrols vehicle movements at SkyNests Prep-delay: the time spentboarding, stowing personal effects or loading an electric payload cartprior to pressing its Go-button and after the appointed time ofdeparture from the dock PPS: precision positioning system QUAD: quieturban air delivery, a system of vehicles to move people and goods by airQusheat: Autonomous passenger seat with electronic ride control toreduce bumpiness Robotic battery swapping, a robot arm that removes andreplaces standard battery packs RDC: robotic delivery cart, agolf-cart-like electric vehicle for hauling EPCs and SBPs Runway endidentification lights, usually strobe lights on either side of thepavement threshold RPM: revolutions per minute SBP: standard batterypack, an energy source in a standard sized container fit for SkyQartsSolenoid-actuated pin-latching System, a fast-acting way to securelylatch items together SkyNest Dock Standards, the uniformly sizedfacilities/capabilities at a QUAD dock SkyNest: one of a series of fivestandardized airparks used in the QUAD system SkyQart: standardizedelectric-powered autonomous QUAD aircraft as types I, II and II Cadencedcoordinated operations at SkyNests, the rapid cadence sequence ofoperations at SkyNests Visual Approach Slope Indicator, a pavementlighting system to guide final approach slopes VTOL: vertical take-offand landing, for example helicopters V_(max): maximum velocity Wheelie:during take-off, an upward tilting of a fuselage that lifts its nosetire off the ground

BRIEF DESCRIPTION OF SEVERAL VIEWS OF THE DRAWINGS

The accompanying drawings are included to provide a furtherunderstanding of the invention and constitute a part of thisspecification. They illustrate the embodiments that comprise theinvention, and together with the description of their components serveto explain the operation of the system.

FIG. 1 depicts a top view of an exemplary Axisymmetric Fuselage Pod(AFP) showing its hard points, ribs and rear hatch.

FIG. 2 depicts a side view of the exemplary Axisymmetric Fuselage Pod(AFP).

FIG. 2A depicts a cross-sectional view of the window frame of thecircular emergency exit window of the AFP.

FIG. 3 depicts a frontal view of the exemplary Axisymmetric Fuselage Pod(AFP).

FIG. 4 depicts a frontal view of an exemplary SkyQart I and II

FIG. 5 is a top view of an exemplary SkyQart I and II

FIG. 6 is a side view of the exemplary SkyQart I and II

FIG. 7 is a frontal view of an exemplary SkyQart III and its wingtipoverlap with a SkyQart I

FIG. 8 is a top view of the exemplary SkyQart III

FIG. 9 is a side view of the exemplary SkyQart III

FIG. 10 shows a frontal view of two SkyQarts configured next to eachother with no overlapping of their wingtips

FIG. 11 shows a frontal view of three different SkyQarts configured nextto each other with overlapping of their wingtips

FIG. 12 depicts a top view of the acceptable noise sphere and its innerdetails

FIG. 13 shows a top view of the relative sizes of an acceptable noisesphere as projected onto the surface of a SkyNest according to aSkyQart's typical trajectory, power setting and height above saidsurface

FIG. 14 shows a top view of a SkyNest I and its components

FIG. 15 shows a top view of the SkyNest II, or dual SkyNest, which is ahigh capacity pairing of two SkyNest l's side-by-side

FIG. 16 shows a top view of the SkyNest III

FIG. 17 shows a top view of the bowl-shaped SkyNest IV

FIG. 18 shows a side view of the SkyNest IV

FIG. 19 shows a perspective view of an exemplary rooftop SkyNest Vconfigured on a rooftop of a structure

FIG. 20 shows a side view of the fast flaps system

FIG. 21 shows a frontal view of the active main landing gear

FIG. 22 shows a side view of the active main landing gear

FIG. 23 shows a frontal view of a SkyQart ultra-quiet propeller

FIG. 24 shows a frontal view of an exemplary central hub of a SkyQartultra-quiet propeller.

FIGS. 25, 26, 27 and 28 depict the details of the autonomous roboticelectric payload cart (EPC) and its seat-latching tracks

FIGS. 29, 30, 31 and 32 depict various types of payloads loaded into theSkyQart AFP

FIG. 33 shows a side view of an exemplary autonomous robotic deliverycart (RDC), its accessories and its fit with an EPC

FIG. 34 shows a frontal view of an exemplary autonomous robotic deliverycart (RDC), its accessories and its fit with an EPC

FIG. 35 shows a top view of an exemplary autonomous robotic deliverycart (RDC), its accessories and its fit with an EPC

FIG. 36 shows a side view of a ramp for off-loading an EPC from and RDC

FIG. 37 shows a top view of the typical size and position of the robotarm and battery charging rack in a SkyNest dock service bay

FIG. 38 shows a side view of a SkyQart and an RDC configured as dockedat a SkyNest dock and depicting the typical size, fit and position ofthe equipment at a SkyNest dock service bay

FIG. 39 shows a graph that depicts the typical take-off acceleration,speed, distance and jerk rate for a SkyQart

FIG. 40 shows a frontal view of the forward surface of a standardbattery pack and its fittings

FIG. 41 shows a frontal view of the rear surface of a standard batterypack and its fittings

FIG. 42 shows a top view of the standard battery pack and its fittings

FIG. 43 shows a side view of the standard battery pack and its fittings

FIG. 44 shows a top view of an exemplary crash cushion

FIG. 45 shows a side view of an exemplary crash cushion

DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENTS

As used herein, the terms comprises, comprising, includes, including,has, having or any other variation thereof, are intended to cover anon-exclusive inclusion. For example, a process, method, strategy,article or apparatus that comprises a list of elements is notnecessarily limited to only those elements but may include otherelements not expressly listed or inherent to such process, method,strategy, article, or apparatus. Also, use of a or an are employed todescribe elements and components described herein. This is done merelyfor convenience and to give a general sense of the scope of theinvention. This description should be read to include one or at leastone and the singular but it also includes the plural unless it isobvious that it is meant otherwise.

GENERAL: The invention is that of the concepts and processes thatinclude the sequence of operations and the important components,electric-powered vehicles and specifications of the distributed airbornemass-transportation system that is herein named “Quiet Urban AirDelivery” (QUAD) and that uses uniquely-capable, one to six seat,electric-powered aircraft (SkyQarts) along with versatile, compatible,standardized electric-powered ground vehicles to provide highlydistributed, high-capacity delivery of both people and cargo acrossurban mega-regions by flying between small, high-proximity SkyNests thatthemselves have specific and standardized dimensions, structures,facilities and features and from which either walking or use of avariety of ground vehicle types, including the EPC and the RDC, canprovide last-mile delivery to doorstep destinations. The SkyNestsprovide a standard embodiment of the loading dock at which thecompatible SkyQarts can be loaded and unloaded rapidly and where rapidrobotic or manual replacement of its standard swappable battery pack(SBP) can take place. The SkyNest, SkyQart, EPC. RDC and SBP are allincluded as important components in this patent, as a combinationcomprising the QUAD processes. The following detailed description of theillustrated embodiments necessarily includes some redundancy with thedescriptions provided in the SUMMARY OF THE INVENTION above, but only tothe extent that it provides the reader the convenience of proximatecontext for the description at hand.

The Axisymmetric Fuselage Pod (AFP)

FIGS. 1, 2, 2A and 3 and shows plan views of the top, side and front,respectively of the axisymmetric fuselage pod (AFP) in accordance withone embodiment of the present invention. Other alternative embodimentsof SkyQarts that do not have AFPs may be used in alternative QUADsystems and still be included in this invention if they retain thecapability of loading and unloading EPCs and or RDCs through a largedoor or hatch in their fuselage while docked.

All of the embedded bulkheads and longerons shown in FIGS. 1, 2 and 3have cross-sections that actually include a wider and gradual tapering(not shown) of their thickness at locations outward from the thick linesthat depict their core structure. Only the core structure of eachbulkhead and longeron is depicted by the thick lines in the figure.

FIGS. 1, 2 and 3 provide top, side and frontal views of the AFP,respectively. FIG. 2A provides a magnified view of the peelable windowframe. Reference number 100 points to a top view of the right side ofthe external surface of the nose of the axisymmetric fuselage pod (AFP),which has a circular cross-section. Reference number 101 points to topand side views of the forward-most structural bulkhead of the AFP, whichdissipates the loads of the nosewheel into the AFP. Reference number 102points to a side view in FIG. 2 of the lower diagonal forward longeronof the AFP. Reference number 102 is omitted in FIG. 1 for clarity.Reference number 103 points to a top view in FIG. 1 and a side view inFIG. 2 of the longitudinal reinforced spine that is embedded into theupper midline of the AFP and helps to carry the loads from the forwardportion of the AFP and its nosewheel to the mono-strut and main wingattachment. Reference number 104 points to a top view in FIG. 1 and aside view in FIG. 2 of the mid-fuselage circular circumferentialstructural bulkhead that is embedded into the skin of the AFP and thatreinforces its floorboards and its other spines, longerons andbulkheads, while also spreading the loads from the forward wingattachment onto the roof of the AFP. In FIG. 2, the reference “FIG. 2A”points to the location of the cross section of the perimeter of thecircular cabin side window that is depicted in larger detail in FIG. 2Abelow. Reference number 105 points to a top view in FIG. 1 and a sideview in FIG. 2 of the curved diagonal embedded bulkhead that joins thelower portion of the mid-fuselage bulkhead to the more aftward circularhatch door bulkhead and spreads the loads from the wing attachment onthe roof of the AFP to its forward structures. Reference number 106points to a top view in FIG. 1 and a side view in FIG. 2 of the curvedhorizontal longeron that joins the rear bulkhead to the middle, diagonaland forward bulkheads and stiffens the side of the AFP. Reference number107 points to a side view of the upper surface of the composite sandwichstructure of the cabin floorboard of the AFP. Reference number 108points to a top view in FIG. 1 and a side view in FIG. 2 of the rearbulkhead of the AFP that stiffens its rear hatch opening and dissipatesloads from both the main wing and the main landing gear. Referencenumber 109 points in FIG. 2 to a side view of the removable flotationmodule #1 that provides enhanced flotation for the SkyQart by fillingthe empty space inside the AFP's rear hatch. Module #1 is typicallyremoved for most payloads. The removal of Module #1 affords extra spaceto allow the seats and the rear baggage bin to recline. Module #1measures nominally 55.9 cm L×114.3 cm H×121.9 cm W at the armrestwaterline, narrowing to 101.6 cm W at the shoulder waterline. Referencenumber 110 points in FIG. 2 to a side view of the larger removableflotation module #2 that can be removed from the rear hatch of the AFPin order to increase the rear cabin volume and enable the hauling ofout-sized cargo items. Excepting the volume of module #1, module #2occupies nearly all of the volume of the rear hatch forward of thefuselage station that is 96.5 cm aft of the hatchline. Reference number111 points in FIG. 2 to a side view of the top portion of the outer skinof the rear hatch of the AFP. Reference number 112 points in FIG. 3 to afrontal view of the rear hatch of the AFP when it is in its fully openedposition, wherein it is swung upward at an 18° angle, the position thatallows it to clear both the dock and the main landing gear. In FIG. 2A,reference number 113 points to a cross-sectional view of thecrosshatched structure that is the juncture of the circular cabin windowon the upper right of the figure with its thicker reinforcing internalperimeter flange. Reference number 114 points to a cross-sectional viewof a representative finger recess in the window's internal perimeterflange. This finger recess and identical others distributed at severalpoints along the window's perimeter serve as grips for a passenger to beable to pull the window inward into the aircraft cabin in the unlikelyevent of having to use the window opening as an emergency escape exit.Reference number 115 points to a cross-sectional view of thehorizontally crosshatched, specially shaped extruded rubber externalsealing strip that seals the outer gap between the window and the windowframe. To increase its surface to volume ratio, this rubber sealingstrip has small nipples that engage into each of the circumferentialgrooves shown in the window's perimeter flange and the window frame. Itwill be noted that this rubber sealing strip forms a flush externalsurface with the outer skin of the AFP when properly pressed and gluedin place. Reference number 116 points to a cross-sectional view of thediagonally crosshatched structure that is the outer wall of the AFP,showing the rounded contour of the edge of its window opening. Thisrounded contour facilitates using the opening as an escape exit.Reference number 117 points to a cross-sectional view of a dashed linethat represents the internal sealing adhesive tape that joins thewindow's perimeter flange to the surface of the inner wall of the AFPand thereby prevents air leakage in or out of the narrow gap around thewindow.

The SkyQart I and SkyQart II

FIGS. 4, 5 and 6 and shows plan views of the front, top and side,respectively of the nominal SkyQart I and II in accordance with oneembodiment of the present invention. Referring now to these FIGS. 4, 5and 6, the detailed features of the exemplary SkyQart I and II areindicated by reference numbers 200 through 238. The SkyQart is sized andproportioned so as to match the dimensions of a standard SkyNest, itsloading dock and its surface carts. Its wing area and span, flap area,propeller diameter, fuselage shape and size, tail volume, groundclearance, landing gear dimensions, center of gravity, cabin volume,battery pack size, and rear hatch door are all scaled to one another soas to allow this aircraft to fulfill the mission requirements andprocesses of the QUAD system. The relative scale of these components inthe 3-view drawing are accurate and are shown together in order toclarify their three-dimensional (3D) shapes. These components are shownin accordance with the dimensions given in the text. When not specified,all items described apply to both SkyQart I and SkyQart II as thenominal interoperable embodiments presented herein.

In FIG. 4, Reference number 200 points to a frontal view of thestarboard tip of the horizontal tail of the SkyQart. Reference number201 points to a frontal view of the upper starboard portion of thevertical stabilizer of the SkyQart. Reference number 202 points to afrontal view of the rectangular container of the emergency ballisticrecovery system, a compact rocket-fired vehicle parachute that iscontained within the tailcone of the SkyQart and that has its attachmentcables embedded into the outer skin of the SkyQart and attached toappropriate hard points of its structure. Reference number 203 points toa frontal view of one of the seven identical propeller blades of theSkyQart's starboard quiet propeller, shown without the propeller spinnerin place. The left or port wing has an identical seven-bladed propellerand it is shown with its axial spinner in place, covering the innermostshank portions of its propeller's blades. Reference number 204 points toa frontal view of the left wingtip of the SkyQart I, showing that it hasa dihedral (upward tilt) of 8.84°. Reference number 205 points to afrontal view of the left wingtip of the SkyQart II, showing that it hasan anhedral (downward tilt) of 11.87°. Reference number 206 points to afrontal view of one of the four flap hinge fins that project down belowthe trailing edge of the lower wing surface. These hinge fins providethe pivot axes for both the forward flap segment and the rear flapsegment of the double slotted wing flaps of the SkyQart's fast flapsystem. Reference number 207 is shown twice for clarity. In FIG. 4,reference number 207 points to a frontal view of the right side of themono-strut that attaches the main wing to the AFP. In FIG. 6, referencenumber 207 points to a side profile view of the leading edge of thatmono-strut, showing its position between the main wing and the AFP.Reference number 208 points to the outer edge of a frontal view of theseatback of the starboard passenger seat for the configuration of theSkyQart in which a total of three seats are used inside the AFP. It willbe noted that the other two seats of this three-seat configuration arealso shown with the same rather thin line thicknesses; there is asymmetrical left-hand or port passenger seat (not labeled), and asmaller midline front seat whose upper left side is labeled as referencenumber 215. Reference number 209 points to the outer edge of a frontalview of the seatback of the starboard passenger seat for the most commonconfiguration of the SkyQart in which a total of two seats,side-by-side, are used inside the AFP. In this common configuration,both the starboard and port passenger seats are depicted with a thickerline width, while the left hand passenger seat is not labeled. Referencenumber 210 points to a dashed line that depicts the outer edge of afrontal view of the seatback of the single, large, midline passengerseat that is used in the single-seat configuration of the SkyQart. Thesingle-seat configuration is used either for exclusive solo privacy (ata higher fare price) or for those cases where an outsized passenger'sgirth or weight require that the SkyQart's payload be limited to thatone person. Reference number 211 points to a frontal view of the leverarm that moves the active main landing gear through its range of motion.This lever arm is rigidly attached to the transverse trunnion bar, shownin frontal view as crosshatched and labeled as reference number 218,whose rotation in the two main landing gear trunnion pillow blockbearings provides the swing axis of the active main landing gear.Reference number 212 points to the right side of the right main landinggear tire of 40.64 cm diameter, which, like its identical mate the leftmain landing gear tire, is mounted on a powerful wheelmotor whose exactrotational position, RPM and power are controlled so as to providetake-off acceleration, regenerative braking on landing, as well asprecisely guided trajectories for taxiing, parking and docking. Notshown in the frontal and top views of the SkyQart are the lightweightwheel fairings, shown in side view in FIG. 6 as reference number 233.These wheel fairings provide a rigid streamlined outer cover for theport and starboard main landing gear tires. Reference number 213 pointsto a frontal view of the bottom surface of the right main landing gearleg of the SkyQart, whose mirror-image, the port main landing gear leg,is shown on the SkyQart's port side. Each main landing gear leg has astout axle on which is mounted its respective tire/wheelmotor. Each mainlanding gear leg is rigidly attached to the transverse trunnion bar,which is labeled as reference number 218. Reference number 214 points toa frontal view of the starboard main landing gear trunnion pillow blockbearing that, along with the left hand pillow block bearing, bears andspreads the loads imparted by the main landing gear's transversetrunnion bar. It will be noted that the port side pillow block bearingis on the left side of the SkyQart at a symmetrical location and that itis a mirror-image of that on the right side. Reference number 215 pointsto the upper outer port side edge of a frontal view of the seatback ofthe single, small, low-set, midline front passenger seat that is used inthe three-seat configuration of the SkyQart. It will be noted that theseat shown as reference number 215 has a smaller width than that shownby reference number 210 in order for it to fit into the more forwardportion of the AFP's cabin. Reference number 216 points to a frontalview of one of the two rear wheelmotors of the autonomous roboticelectric payload cart (EPC). An identical, not-labeled, mirror-imagerear wheelmotor can be seen on the opposite side of the EPC with thisview. Reference number 217 points to a frontal view of the starboardlatching pin of one of the SkyQart's solenoid bodies, showing that it isinserted inside the side wall of the floorboard of the EPC in order tosecurely pin-latch the EPC to the SkyQart. The structure that securesthis solenoid body to the inside wall of the SkyQart is not depicted inorder to enhance clarity. Reference number 218, as mentioned above,points to the transverse trunnion bar of the main landing gear.Reference number 219 points to a frontal view of the bottom edge of theoval shaped DC fast-charging port, shown in horizontal crosshatch, inits standardized location under the floorboard of the SkyQart and justlateral to the SBP. Reference number 220 points to a frontal view of thebottom surface of the standard swappable battery pack (SBP) showing itssize and location in the belly of the AFP along with the drawer slideson its port and starboard sides. Reference number 221 points to a topview in FIG. 5 of the starboard axisymmetric propeller spinner with its40.64 cm base diameter. There is an identical spinner shown in top viewon the port side propeller. These spinners enclose the controllablepitch hubs of the starboard and port propellers. Reference number 222points to a top view of the starboard motor nacelle that provides astructural mount and streamlined covering for the right side propellermotor and its accessories. A symmetrical nacelle that is not labeled isshown on the port side of the SkyQart. These nacelles extend thepropellers well forward of the wing's leading edge in order to helpensure undisturbed air inflow to the propellers, a feature that isimportant to minimizing propeller noise. Reference number 223 points toa top view of the leading edge of the right main wing. Reference number224 points to the trailing edge of the starboard aileron, shown in topview in FIG. 5. There is a not-labeled mirror-image of the right aileronsymmetrically placed on the trailing edge of the left wing, comprisingthe left aileron. Reference number 225 points to the trailing edge ofthe right main wing's double slotted flap, whose full chord-wise extentwhen nested inside the wing is depicted by the dashed line just forwardof that trailing edge. A symmetrical mirror-image double slotted flapand nested chord limit line is likewise depicted for the left main wing.Reference number 226 points to a side view of the top surface of thetapering tailcone structure that joins the main wing to the horizontaland vertical tail surfaces. This tailcone has a circular cross-sectionwhen viewed from the frontal perspective. Reference number 227 points toa side view in FIG. 6 of the intersection of the SkyQart's 30.5 cmdiameter nose tire with the ground plane, as would occur with a fullyloaded SkyQart at static conditions on a level parking ramp. Referencenumber 228 points to the bottom edge of the SkyQart's right sidewindshield. Reference number 229 points to a side view of the bottomsurface of the SkyQart's cabin floor structure. Reference number 230points to a side view of the outer skin of the belly of the SkyQart'sAFP, whose skin is comprised of a 2.54 cm thick composite sandwichstructure. Reference number 231 points to a side view of one of therectangular latching solenoid bodies that are arrayed inside the SkyQartand that serve to pin-latch the EPC in place. Other such solenoid bodiesfor latching the EPC are omitted from FIG. 6 to simplify the drawing.The structure that attaches these solenoid bodies to the interior of theSkyQart likewise is not depicted here in order to simplify. Referencenumber 232 points to a side view of the Qusheat ride control seat whichis the electromechanical pedestal that fits underneath and smartly moveseach seat bottom so as to reduce the impact of air turbulence on theSkyQart passengers. Reference number 233 points to the aforementionedtruncated wheel fairing for the main landing gear. Reference number 234points to a top view of the outline of the AFP's rear hatch when it hasbeen swung open 90° into its fully open position. The rear hatch swingsopen on a hinge that is located on the port side of the SkyQart's AFP.That hinge has a hinge axis that is tilted 1080 above the horizontalplane and this causes the rear hatch to swing along a path that makes an18° angle above the horizontal. Reference number 235 points to the portrear side of the SkyQart's rear hatch when it is in the closed positionas viewed from above. Reference number 236 points to the trailing edgeof the movable rudder on the rear portion of the SkyQart's verticaltail. Reference number 237 points to a frontal view of the left-hand oneof the two 6.86 mm diameter dock pin alignment receptacle holes in thefloorboard of the SkyQart. It can be seen that the starboard hole thatis mate to this left-hand alignment hole is symmetrically placed andthat these two holes are nominally 81.3 cm apart, straddling the midlineof the SkyQart. In FIG. 4, reference number 238 points to a frontal viewof the starboard wing's optional diagonal wing strut, shown as anoutline that has its upper end attached to the main wing spar through anopening in the lower surface of the wing on or near the inboard edge ofthe motor nacelle. That strut has its lower end attached structurally tothe strong main longeron that is embedded into the sidewall of the AFP.There is a mirror image of this diagonal wing strut shown in frontalview under the left wing of the SkyQart. Reference number 238 is alsodepicted as a thin rectangle in the side view shown in FIG. 6, showingits position relative to the wing and AFP. NOTE: such optional diagonalwing struts are not shown in the SkyQarts in any other drawings orfigures herein.

The SkyQart III

SkyQart III is shown in FIGS. 7, 8 and 9 in frontal, top and side viewsalong with its wingtip overlap with a SkyQart II as when docked at aSkyNest. The internal parts of each AFP are not labeled in the frontalview shown in FIG. 7 because those parts are identical to those shown inFIGS. 4, 5 and 6, where the contents were identified. Where partscommonality exists between the SkyQart II and the SkyQarts T and II, theshared or common parts in the SkyQart III are not labeled in FIGS. 7, 8and 9. Similarly, where there exist and are shown more than oneidentical parts of a given type, only one of those parts will be labeledwith a reference number. The SkyQart III is easily recognizable asdifferent from the SkyQarts I and II because it has three propellersrather than two. The reference number 300 in FIG. 7, points to a frontalview of the top surface of the main wing center section of the SkyQartIII. This center section is comprised of the same airfoil section as theoutboard wing panels and it has a constant chord. It is also equippedwith full-span double slotted flaps that operate with the fast flapssystem. Reference number 301 points to a frontal view of the uppersurface of the horizontal tail of the SkyQart III, which is larger thanthat of the SkyQarts I and II. Reference number 302 points to a frontalview of the starboard vertical tail surface of the SkyQart III. It willbe noted that this starboard vertical tail surface has a matching portside mirror image vertical tail surface and that these two surfacestogether comprise the total vertical tail area of the SkyQart III. Thesetwo surfaces also are seen to secure and connect the horizontal tail tothe aircraft. Reference number 303 points to a frontal view of thethrust axis of the seven bladed propeller on the starboard wing, whichaxis, as shown, is higher above ground level than the comparablepropeller on the SkyQarts I and II, because it is mounted above ratherthan below the chordline of the outer wing. It will be noted that thepropeller indicated by reference number 303 has a matching seven bladedpropeller mounted symmetrically on the port side wing of the SkyQartIII. Reference number 304 points to a frontal view of the starboardwingtip of the SkyQart III, showing that it is tilted upward from thehorizontal at an angle of 9.58° in order to facility the overlapping ofwingtips with other SkyQart II aircraft at the dock of the SkyNest.Reference number 305 points to a frontal view of the trailing edge ofthe rear flap segment of the fully extended double-slotted wing flapthat is mounted to the rear portion of the main wing of the SkyQart III.Reference number 306 points to a frontal view of the lower edge of thefully opened rear hatch of the starboard AFP of the SkyQart III. It willbe noted that this starboard rear hatch opens toward the starboardwingtip while the symmetrical matching rear hatch on the SkyQart III'sport side AFP opens toward the left wingtip, as does that of the SkyQartII that is parked adjacent to the left wingtip of the SkyQart III inFIG. 7. Reference number 307 points to a frontal view of the thrust axisof the seven-bladed propeller at the midline of the center section ofthe main wing of the SkyQart II. This propeller has a diameter of 3.05 mand is identical to all other propellers in FIGS. 7, 8 and 9. Referencenumber 308 points to a frontal view of the clearance gap between theoverlapping wingtips of the SkyQart III and SkyQart II, whose minimumdimension is nominally 18.3 cm. This dimension assumes that bothaircraft are parked on level ground at their appropriate separationinterval of 9.144 m between their adjacent nosewheels. Reference number309 points to a top view of the forward edge of the nose-tire of thestarboard AFP of the SkyQart III. It can be noted that there is anidentical nose-tire symmetrically positioned on the port side AFP of theSkyQart III. Both of these nose tires can be retracted into theirrespective AFPs during flight. Reference number 310 points to a top viewof the leading edge of the SkyQart III's starboard main wing. It can benoted that the SkyQart III has a port main wing that is a mirror imageof this starboard main wing, and that the propellers on the nacelles ofeach of those main wings are symmetrically placed relative to thelongitudinal centerline of the aircraft. Reference number 311 points toa top view of the trailing edge of the starboard aileron on the outboardportion of the starboard main wing of the SkyQart III. It can be notedthat there is also a mirror-image port aileron symmetrically placed onthe outboard portion of the port main wing. Reference number 312 pointsto a top view of the trailing edge of the starboard main wing's doubleslotted flap in its fully retracted position. It can be noted that thereis also a mirror-image of this flap symmetrically placed on the SkyQartIII's port main wing. Reference number 313 points to the starboard AFP'sstarboard main landing gear tire of 40.64 cm outside diameter. It can beseen that each AFP on the SkyQart III has two such main landing geartires, a starboard and a port, making a total of four such main landinggear tires in addition to the two nose-tires. Reference number 314points to one of the two rectangular enclosures for the ballisticrecovery system parachute housings that are located along the midline ofeach AFP and above the main wing. These two ballistic recovery systemunits are programmed to deploy their rocket powered parachutessimultaneously in the event of an unrecoverable loss of control orin-flight structural failure. Reference number 315 points to a side viewof one of the tapering tailcones of the SkyQart III. The tailcones arethe beam-like structures that join the main wing to each of the SkyQartIII's vertical tail surfaces. These tailcones are very similar but notidentical in shape to those of the SkyQarts I and II and each of thesetailcones has a circular cross-section in frontal view. Reference number316 points to a top view of the trailing edge of the fully retracteddouble slotted flap on the main wing center section. These flaps work insynchrony with the flaps on the outer main wing panels as parts of thefast flap system. Reference number 317 points to a side view of therearmost surface of one of the two fully retracted nose-tires to showhow its nests within its AFP.

Overlapping Wingtips

FIGS. 10 and 11 depict two frontal views of the dimensions involved intwo overlapping wingtip situations for various SkyQarts that are dockedat a SkyNest. The main purpose of these figures is to show howoverlapping wingtips enable a more efficient use of dock space at theSkyNest. The docking of SkyQarts at a SkyNest must necessarily be spacedat regular intervals that match the QUAD standard for the spacing ofbattery swap infrastructure at the dock. That QUAD standard is 4.57 mbetween battery swapping stations. Each battery swapping station at aQUAD dock has a pair of precision positioning system transponderreceiver plates mounted on the face of the dock on either side of thecenter point of the battery swapping station. Each precision positioningsystem transponder plate receives four convergent He—Ne laser beams fromthe emitters on the aft face of the sidewalls of the SkyQart's rearhatch opening, and they process the information from the laserimpingement pattern into a wireless transmission back to that SkyQart toguide the movement of the SkyQart's active main landing gear wheelmotorsto steer the SkyQart into the exact horizontal and vertical alignmentwith the dock's battery swapping station. To help ensure precisedocking, this precision positioning system uses a combination ofmultiple miniature electronic sensors in sequenced sensor fusion inaddition to its convergent He—Ne laser guidance system. Co-located onthe dock face with these precision positioning system transponderreceiver plates are two capacitive proximity sensors, which help guidethe SkyQart to park exactly at the appropriate station at the dock witha 3D precision of nominally 2.0 mm. (These plates and sensors are toosmall to depict in the drawings.) This guidance is assisted by theActive Main Landing Gear, which is able to control and set the rideheight of the SkyQart during its dock maneuvering. When two SkyQart I'sdock next to each other, their upturned wingtips prevent them fromparking with overlapping wingtips and this causes them to have to parkwith their nose tires 13.7 m apart. Reference number 400 in FIG. 10points to a line denoting the dock span distance of 27.73 m spanned bythese two SkyQarts' wings when they are docked with this amount ofseparation. Reference number 401 points to a frontal view of theupturned right wingtip of the SkyQart I. Reference number 402 points tothe ground level of the pavement at a SkyNest dock. Reference number 403points to one of several interval alignment markers for the nose tire ofa docking SkyQart so as to align the aircraft with the battery swappingstations at the dock. It will be noted in FIG. 10 that these intervalmarkers are each equally spaced along the ground pavement level atintervals of 4.57 in, a dimension shown by a double arrow and labeled asreference number 407 in FIG. 11. Reference number 408 points to a doublearrow that depicts the dimension of 20.14 m, which is the dock span thatobtains when a SkyQart II and SkyQart I dock side-by-side withoverlapping wingtips and with their nose-tires 9.14 m apart. Incontrast, when two SkyQart I's or two SkyQart's II dock side-by-side inalignment with the dock's battery swapping pathways, they must do sowithout overlapping wingtips, resulting in their nose-tires being placed13.7 m apart. This larger separation results in their combined spanwisedimension, shown in FIG. 10 as the double arrow whose dimension islabeled as reference number 400 and consuming a total dock span of 24.73m, nearly 5 meters more dock span than consumed by the pairing ofoverlapping SkyQarts I and II. If each SkyQart is configured to carrythree passengers, then the efficient, overlapping docking of twodissimilar SkyQarts can achieve a maximum passenger density of sixpassengers in 20 m of dock span, equating to 3.33 m of dock span forevery passenger. If the less efficient docking of two identical SkyQartsis similarly examined, it results in six passengers in 24.73 m of dockspan, equating to 4.12 m of dock span for every passenger. Theoverlapping wingtips thus provide a roughly 25% improvement in dockefficiency. Similarly, when an ideal mix of SkyQart I, II and III aredocked side-by-side in alignment with the dock's battery swappingpathways, as shown in FIG. 11, the total combined spanwise dimension ofthat dock span is 33.76 m and is depicted by the double arrow that islabeled as reference number 406 in FIG. 11. If each AFP of these threeSkyQarts carries three passengers, this example results in twelvepassengers in 33.76 m of dock span, which equates to only 2.81 m of dockspan per passenger. Reference number 301 points to a frontal view of theupper surface of the horizontal tail of the SkyQart III that is dockedwith overlapping of its right wingtip. Reference number 405 points to afrontal view of the horizontal tail of a SkyQart II that is docked withoverlapping of its wingtips.

The Acceptable Noise Sphere (ANS)

FIGS. 12 and 13 show the acceptable noise sphere concept. The acceptablenoise sphere is an innovative aircraft noise depiction tool for thedesign and sizing of SkyNests for the QUAD system. The size of thetwo-dimensional intersection of the acceptable noise sphere with thepavement surface of a SkyNest depends on the SkyQart's height aboveground and its power settings. Several airport noise survey studies havecompared aircraft noise levels in the neighborhood of airports, measuredin decibels, with the percentage of people in those areas who werehighly annoyed by those noise levels. The results of those studiesindicate that, to be community acceptable and to comply with FAAstandards, airports should be sized so that the noise level at anairport's outer boundaries is kept low enough that no more than 10% ofairport neighbors are highly annoyed. To reliably accomplish this, theaverage noise at the SkyNest boundaries with noise-sensitive developedareas, measured using the Community Noise Equivalent Level (CNEL), whichis also known as the “day, evening, night” metric signified as L_(den),would have to remain below 54.7 dBA L_(den), and preferablysubstantially less than that. This level scales with the standard fornoise limitation required for machines operating in U.S. National Parks,where noise must be kept below 60 dBA at a 15.24 m sideline. ThatNational Park noise requirement translates to a noise level of 51.6 dBAat a 40 m sideline. A body of evidence indicates that noise must be keptespecially low when SkyQart aircraft operate with frequent take-offs andlandings at short time intervals or at night, both of which willcommonly occur at busy SkyNests in the QUAD system. Accordingly, areasonable initial goal for the quietness of all SkyQarts will be atake-off noise level, measured during full-power take-off, that remainsbelow 55 dBA LA_(eq), 5 s at a 40 m sideline drawn from the midline ofthe aircraft's nose. The LA_(eq), 5 s metric denotes the average noiselevel, measured on the A scale during a 5 second interval. This level of55 dBA LA_(eq) at a 40 m sideline appears to be one whose acceptablenoise sphere can be kept from impinging on noise-sensitive developedareas by all 5 types of SkyNests embodied herein for the QUAD system.The community noise equivalent level, designated as CNEL, is anothercommonly used metric for noise, and is equivalent to the L_(den). Itconsists of a weighted average sound level over a 24 hour period, with apenalty of 5 dB added between 7 pm and 10 pm, and a penalty of 10 dBadded for the nighttime hours of 10 pm to 7 am. The noise emissions ofthe SkyQarts I, II and III included in this invention are expected toachieve the requisite low noise levels, possibly getting as low as 40dBA CNEL at the 40 m sideline. The acceptable noise sphere is the toolthat is both directional and scalable. The acceptable noise sphereheading line is an arrow that is oriented in the direction in which theaircraft is traveling. Although the acceptable noise sphere is shown asa two-dimensional circular object on maps, it is in reality a virtualthree-dimensional sphere. The acceptable noise sphere can be shown in aSkyNest layout plan at various points along the trajectory of a SkyQartas simply the acceptable noise sphere scaled in size to be only thetwo-dimensional slice of it that intersects with the ground surface ofthe SkyNest. When so applied to a SkyNest layout plan, the acceptablenoise sphere at a given location is shown as a circle whose area is thatspace outside which the noise level of the passing aircraft is at orbelow the acceptable limit. This actual area will change at differentlocations on the SkyNest depending upon the height of the SkyQart aboveground level at said location as well depending upon the aircraft'sspeed, power setting, flap setting, thrust or drag level, etc. The goalin the QUAD system is to have the height above ground of the SkyQartaircraft flying over the SkyNest boundary always be higher than theradius of its acceptable noise sphere at that point. When the SkyQartaircraft's height above ground level is exactly equal to its acceptablenoise sphere radius, then its acceptable noise sphere projection ontothe ground would be just a tiny dot, and that one dot would be thelocation at which there was a localized noise level at the limit ofacceptability, with lower noise levels at all other locations nearby.Reference number 500 points to the circle that depicts the outer rim ofa representative acceptable noise sphere that includes the typicaldirectionalities of the SkyQart's propeller noise. This circle depictsthe radius from the SkyQart's AFP at which its noise emissions will notexceed acceptable levels and outside of which the SkyQart's noise willbe quiet enough to ensure that less than 10% of people outside thatradius will be highly annoyed. Reference number 501 points to thedirectionality axis of the acceptable noise sphere, an arrow line that,by convention herein, is aligned with the heading of the aircraft andthat is assigned the angle of 0°. Reference number 502 points to theforward ‘wing’ of the butterfly-shaped noise contours that arecalculated for the aircraft's propeller take-off noise using the Gutinpropeller noise mathematical formula. The largest span or radius of thisforward butterfly wing contour is typically shorter than that of therear butterfly wing of the noise contour, which larger rear wing contouris shown as reference number 503. Inside reference number 503 is shownthe straight line that denotes the rearward azimuth of maximum noise,which is labeled as being at 105°, a fairly typical angle for peakpropeller noise radiation. Reference number 504 points to the relativelylarge acceptable noise sphere that would apply at the landing touch-downlocation of the SkyQart on the SkyNest shown in FIG. 13, where theaircraft typically executes a sudden increase in propeller and tirenoise due to 1) its use of a rapid increase in propeller thrust toarrest its sink rate by blowing on the fully extended double slottedwing flaps and 2) the onset of a touchdown tire chirp, tire spool-up andthe rolling noise of the main landing gear tires. Note that theacceptable noise sphere shown as reference number 504 has its axis ofdirectionality oriented in the direction that the SkyQart is landing.Reference number 505 points to the outer circle of the SkyQart'sacceptable noise sphere that is located at the point on the SkyNestpavement where the SkyQart executes its liftoff on take-off. This is thelocation where the fast rolling speed of the SkyQart's tires and itshigh level of propeller thrust produce the greatest amount of noise.Consequently, the two-dimensional circle that represents the acceptablenoise sphere labeled as 505 is the largest diameter acceptable noisesphere on this SkyNest diagram. Note that even with its large diameter,the reference number 505 acceptable noise sphere circle shows that itsacceptable noise level is contained within the confines of the SkyNestland parcel shown in FIG. 13. Reference number 506 points to a top viewof the left wingtip of a SkyQart I or II, showing it to be heading inthe same direction as the heading of the reference number 505 acceptablenoise sphere on the take-off portion of the SkyNest pavement. There arethree other identical SkyQart aircraft shown with their headingdirection on the typical trajectory paths on this SkyNest diagram.Reference number 507 points to the outer long edge of the largerectangle that represents a top view of the area of the SkyNest landparcel, an area that encloses the pavement, two taxiways and a dockarea. It will be seen that the pavement portion of this SkyNest islabeled with large opposing heading numbers 14 and 32. Reference number508 points to a top view of the center of the take-off portion of theSkyNest pavement. Reference number 509 points to a top view of themedium-sized circle of the acceptable noise sphere (projected onto thesurface of the SkyNest) that depicts the noise emissions of a SkyQartthat is descending power-off on its curvilinear final landing approach,the curved traffic pattern of its descent path to the SkyNest, whereinsaid descent path is depicted by the curved dashed line labeled asreference number 510 in FIG. 13. It will be noted that the outer circleof reference number 509 represents the boundary outside which theSkyQart's noise emissions at ground level are nominally below 48 dBA atthis point along its descent path. Reference number 511 points to thevery small circular area that exists at the point along the curvilinearfinal landing approach descent path that represents the boundary(projected onto the surface of the SkyNest) outside which the SkyQart'snoise emissions at ground level are below the acceptable noise limit atthis point during its descent. Reference number 511 is a very small areabecause of two conditions at its location along the descent path; 1) theSkyQart's acceptable noise sphere is small due to its use of a very lowpower setting during descent, and 2) the SkyQart is flying its descentat a height well above 30 m above the ground so that the portion of thesmall acceptable noise sphere that intersects the surface of the SkyNestis very small. Reference number 512 points to the outer circle of theprojection of the SkyQart's acceptable noise sphere onto the surface ofthe SkyNest at the location where the SkyQart is climbing out on acurvilinear path after take-off on the SkyNest pavement. Referencenumber 512 is of medium size because the SkyQart is climbing withmaximum power at that point. Reference number 512 is smaller thanreference number 505 (the maximum power take-off acceptable noise sphereprojection) because at the location of reference number 512 the SkyQarthas climbed to reach a height of several meters above ground level. Thisheight reduces the area of the acceptable noise sphere's intersectionwith the ground surface. Reference number 513 points to a top view ofthe curvilinear flight path of the SkyQart's climb out from the SkyNest,shown as a dashed line. Reference number 514 points to the very smallcircular area that exists at the point along the SkyQart's curvilinearclimb out path that represents the boundary (projected onto the surfaceof the SkyNest) outside which the SkyQart's noise emissions at groundlevel are quieter than the acceptable noise level. The small size ofreference number 514 reflects the fact that it is located at a pointalong the climb out path where the SkyQart has climbed to a height thatis more than 30 m above the surface of the SkyNest, where the portion ofthe acceptable noise sphere that intersects the ground is a smallcircle. The size and position of the four acceptable noise spheres ofdiffering sizes that are projected on the SkyNest diagram in FIG. 13depict one example in which the noise of the departing and arrivingSkyQart can be seen to be kept at or below acceptable levels at allpoints within the boundaries of the SkyNest. This example illustratesthe usefulness of the acceptable noise sphere as a tool in planning thesize of the SkyNest so that it will be community acceptable.

The SkyNest I

FIG. 14 which depicts a standard 1.28 ha nominal SkyNest I with itspavement and dock facilities, SkyQarts. EPCs, RDCs, crash cushions andthe concepts of their operations. Nominal embodiments of thesecomponents have each been described above in detail and, together withtheir sub-components, comprise the main innovations of this invention.Their interoperating and interdependent processes are best depicted bycombining all of them into one detailed drawing. Accordingly, theembodiment of the QUAD process in FIG. 14 depicts in fine detail anideal sequence and cadence of operations of those components. Whilethese operations are generic and can be applied at many differentlysized SkyNests, they nevertheless represent in FIG. 14 an extreme caseof expeditiousness made possible by sentient autonomous vehicles thatoperate with very small separations. This extreme cadence provides oneSkyQart departure and one landing every 10 seconds. The processdescribed is that of a fully implemented, autonomous QUAD systemoperating at maximum capacity. The process described here is calledcadenced coordinated operations at SkyNests and it sets the standard foroperations that can provide a very rapid turnaround time for a landingSkyQart. Cadenced coordinated operations at SkyNests are a componentintegral to this patent. Cadenced coordinated operations at SkyNestsmaximizes capacity and efficiency in order to determine the realisticlimits for capacity, size, speeds and distances that, in turn, can beused to develop the necessary standards for the smallest practicalSkyNest that can work in a fully autonomous, optimized QUAD system.Keeping SkyNests as small as possible is what enables them to beaffordably built and to be sited close to where people live and work, animportant feature if they are to reach a mass-market and providemeaningful benefits to the public transportation system. The 1.28 hasize of the SkyNest I in FIG. 14 is presumed to be the smallest sizethat can be located fully inside a quiet residential area and stillconfine the aircraft noise to within its boundaries. Smaller SkyNestscan be used in other, less noise sensitive settings. For example, if atleast three of its sides have borders on open space or open water, aSkyNest can be as small as 0.61 ha and still provide the required noisecontainment. QUAD SkyNests located within urban and industrial areaswhere high levels of ambient noise exist, and those with fewer flightoperations that are located within large, privately-owned campuses,ranches or family compounds, can also be smaller than the standardSkyNest I depicted in FIG. 14, but each must still provide containmentof the acceptable noise sphere at the public margins of thoseproperties. SkyNests larger than 1.28 ha can have similar operationalcadences to those shown in FIG. 14, but, for system-wide uniformity, thesize, speeds and landing distances of the SkyQarts operating there muststill be compatible for use at all other SkyNests across the QUADsystem, including the smallest SkyNests. It will be possible to ‘carveout’ various sizes of SkyNests within existing larger conventionaltake-off and landing airports in order to create early implementationsof the QUAD system. According to the requirements for cadencedcoordinated operations at SkyNests and the performance envelope of theSkyQarts, this invention of the QUAD transportation system is limited toSkyNests of sizes of less than 5.0 ha. In the example of operationalprocesses shown in FIG. 14, the aircraft that are airborne within theSkyNest boundaries are operating at a nominal 24 m/sec and those thatare taxiing on the SkyNest surface are moving at a nominal 7.6 m/sec.These are optimum speeds that relate the distances that can beexpeditiously covered in each 10-second operational step in the sequenceof autonomous landing, taxiing to the loading dock, taxiing to thedeparture pavement and taking off again, to the actual size of theSkyNest land parcel. The ideal fast cadences for autonomous loading andunloading of payloads on the SkyNest's dock are likewise modeled forvery rapid turnaround times that rely on robotic equipment andpre-loaded EPCs. In FIG. 14, reference number 600 points to the leftwingtip of a SkyQart I or II that is positioned at the brake releasepoint on the active pavement (runway 14) of the SkyNest. Referencenumber 601 points to the crosshatched area that represents the SkyNesttake-off pavement. Reference number 602 points to a double arrow whoselocation and length represent the portion of the pavement used in anominal take-off roll of a SkyQart in dry, no wind conditions. Referencenumber 603 points to a curved dotted line that represents the groundtrack of the curved traffic pattern climb-out path of the SkyQart duringa normal departure. Reference number 604 points to the intersection ofthe landing approach path with the take-off departure path of theSkyQart projected onto the surface of the SkyNest at point labeled “X”,a point at which both the exact timing and 3D positions of the passingaircraft must be consistently and continuously coordinated in 4D toavoid conflict. That coordination is jointly performed by the networkedsituational awareness system and the autonomous control systems on-boardeach SkyQart. The networked situational awareness and autonomous controlsystem are important components of this patent. Reference number 605points to the left wingtip of a SkyQart that is located at the landingtouch-down point on the SkyNest pavement. Reference number 606 points toa double arrow that depicts the nominal length that is the distance ofthe short landing roll of the SkyQart at the SkyNest. This double arrow(606) terminates at the point, labeled as reference number 611, at whichthe SkyQart has sufficiently slowed its rolling speed to enable it tomake a right turn to exit the landing pavement. Reference number 607points to a location labeled as “K” along the curved climb-out path ofthe SkyQart, at which it would reach a height of 19.2 m above groundlevel. This height at this location above the SkyNest ensures that thedeparting SkyQarts are well above the height of any SkyQarts that wouldbe concurrently taxiing on the surface of the subjacent Taxiway II.Reference number 608 points to the starboard wingtip of a SkyQart I orII that has departed from position “E” at the dock and is heading towardTaxiway II in order to proceed to the departure end of the runway 14.Reference number 609 points to the surface of Taxiway II. Referencenumber 610 points to the corner of an outline of the aircraftmaintenance hangar that is large enough to contain a SkyQart III.Reference number 611 points to the port wingtip of a SkyQart I or IIthat is in position to turn off of the pavement after landing. Referencenumber 612 points to the QUAD crash cushion at the end of the pavement.An identical crash cushion is located at the opposite end of thepavement. In other embodiments of the SkyNest, the crash cushion is amovable device that can be positioned at the end of any active runwaypavement. Reference number 613 points to a SkyQart that has just turnedoff of the runway pavement after landing and is in the process oftaxiing to park at the dock. This SkyQart is traveling at 7.6 m/sec andthereby can travel 76 m in 10 seconds. Reference number 614 points to aposition labeled as “Y” along the surface projection of the SkyQart'slanding approach. Position “Y” is the point at which the landingSkyQart, after steeply descending over both Taxiway I and Taxiway II,has descended to a height of just 8.2 m above the surface of theSkyNest. This height of 8.2 m is enough to ensure that the descendingSkyQart will readily clear the SkyQarts that are taxiing on the surfaceof Taxiway II. Reference number 615 points to the port wingtip of aSkyQart that has completed its taxing for take-off and is in a holdposition awaiting entry onto the active runway 14. Reference number 616points to a SkyQart III that is taxiing on Taxiway II toward the holdposition that is labeled as reference number 615. It will be noted thatthe longer wingspan of the nominal interoperable SkyQart III spans theentire 15.24 m width of Taxiway II, emphasizing the practical importanceof limiting the wingspan of SkyQarts in order to limit the size of theland parcel required for a SkyNest. Reference number 617 points to aSkyQart that is taxiing on Taxiway I from the position labeled asreference number 613 toward the position labeled as reference number 619where it will stop its forward taxiing and stop to become able toreverse the rotation of its main landing gear wheelmotors so as toback-in to a vacant position labeled as “P” at the dock. Referencenumber 618 points to the curved, dashed line that is the curved trafficpattern projection onto the surface of the SkyNest of the curved landingapproach path flown by a SkyQart. Reference number 620 points to a linethat is both the proximal edge of Taxiway I, and the distal edge of thelarge, coarsely crosshatched area that represents the nominal 167.6m×48.8 m solar panel array that covers the dock and adjacent streetarea. Reference number 621 points to the centrally located passengerlounge on the dock area, wherein are found restrooms, telephones, aSkyNest service counter and/or a SkyNest kiosk for making and paying fortravel reservations, seating areas, vending machines, etc. Referencenumber 622 points to the edge of a finely crosshatched area thatrepresents the dock that borders the aircraft operations area. The dockhas its aircraft docking stations for SkyQarts spaced at 4.57 mintervals and it will be noted that the SkyQarts I and II are shown tobe docked with overlapping wingtips. Reference number 623 points to thelocation marked as “0” which is the position at which the SkyQart on itsapproach to landing has descended to a 30 m height above the surface ofthe SkyNest. This 30 m height is safely above the solar panel array anddock. Reference number 624 points to the trapezoidal outline of one ofmany autonomous robotic electric payload carts (EPCs) on the docksurface. The several EPCs shown on the dock are to illustrate the largeamount of bi-directional cart traffic on the dock, with each EPC at somephase of loading or unloading passengers or payload, rolling into or outof a docked SkyQart, or rolling onto or off of an autonomous roboticdelivery cart (RDC) at the street side of the dock. Reference number 625points to an RDC at the dock. It is laden with an EPC on its surface. Itcan be noted that several other RDCs are also at the dock, some with andsome without EPCs on their surface. Reference number 626 points to oneof the sets of stairs that enables passengers to climb up from streetlevel onto the dock, whose surface is 47 cm above street level. Severalsets of such stairs are shown in FIG. 14. Each set of such stairs is1.83 m wide with a 15.66 cm rise and a 35.56 cm tread. Reference number627 points to one of several ADA compliant ramps to enable wheelchairpassengers to move from street level up onto the dock. Reference number628 points to the 2.44 m wide public sidewalk that borders the SkyNest.Reference number 629 points to the 1.83 m wide bicycle lane that bordersthe sidewalk. Reference number 630 points to the 2.44 m wide parallelparking spaces that border and protect the bicycle lane. Referencenumber 631 points to the 3.05 m wide single car lane that borders theparallel parking spaces. Reference number 632 points to the 1.83 m widecenter divide that separates the car lane from the electric mini-transitbus lane. Reference numbers 633 and 634 point to the two centralelectric mini-transit bus lanes, each of which is 2.44 m wide. Referencenumber 635 points to the 1.83 m wide center divide that separates theopposite car lane from the electric mini-transit bus lane. Referencenumber 636 points to the 3.05 m wide opposite direction single car lane.Reference number 637 points to the 2.44 m wide parallel parking lanethat borders the opposite direction single car lane. Reference number638 points to the 1.83 m wide opposite bicycle lane. Reference number639 points to the 2.44 m wide opposite sidewalk. The area in FIG. 14that is occupied by reference numbers 628 to 639 inclusive is indicatedwith a coarse diagonal crosshatch because these items comprise oneembodiment of the type of street and sidewalk areas that would be thepublic amenities adjacent to a typical SkyNest I. These amenities arenot a part of the SkyNest I land parcel but are a generic format ofstreet and sidewalk that would likely be provided by localmunicipalities in order to provide good surface access to any type ofSkyNest. Reference number 640 points to the dashed line that outlinesthe rectangular outer boundary of the SkyNest I parcel as being anominal 167.6 m×76.2 m. Reference number 641 points to an RDC that hasno EPC on it. Reference number 642 points to a transit bus parked at theSkyNest I. Reference number 643 points to a bicycle rack in the parallelparking lane at the SkyNest I. Reference number 644 points to thelocation labeled as “C” at which the departing SkyQart, is climbing outfrom the SkyNest I and has reached a height of 40 m above ground level.At this height and location, its noise emissions are nearlyimperceptible on the ground. Reference number 645 points to the cargoservice building in which cargo and parcels are loaded and unloaded fromEPCs and cargo containers. The cargo service building is appropriatelylocated adjacent to what is labeled as reference number 646, the truckdock at which shipping and receiving of larger cargo takes place. Alarge solar energy array (reference number 620) may be installed abovethe dock area at SkyNests of several types as well as above adjacentstreets, land parcels and buildings in order to provide renewable energyfor the battery charging processes that take place at the SkyNest.

Other amenities not shown in FIG. 14 but important at any SkyNest aredeer-fencing, taxiway and pavement lighting, laser-guided and guidelinedocking alignment, weather detection and navigational aids, includingbut not limited to one or more of the following: differential GPS,Visual Approach Slope indicator, Runway End Identification Lights,ceilometer. Doppler wind lidar, transmissometer, Forward LookingInfra-red Radar, Diode Laser Centerline Localizer and Diode LaserGlideslope Indicator. Ancillary businesses co-located at SkyNests butnot shown in FIG. 14, though not required, are anticipated to includebusinesses like coffee shops, shipping services, convenience stores,restaurants, etc.

A more detailed explanation of the cadenced coordinated operations atSkyNests process above is as follows: A SkyQart aircraft is shown at thelower left portion of FIG. 14, as it enters the SkyNest boundary duringits landing approach. For noise abatement purposes, it descends steeplywith a shallow, roughly 300 bank angle, (and with its propellersproducing drag by wind-milling in electricity regeneration mode) from aheight of nominally 30 m above ground level at the position labeled withan “O” as reference number 623 in FIG. 14, at which position its noiseemissions are so low as to be nearly imperceptible on the ground. Itproceeds to descend from there along the curved path shown as the dashedline labeled as reference number 618, toward the landing portion of theSkyNest pavement. That curved path is deliberate because it provides theSkyQart with a longer distance over which to complete its descent overthe SkyNest property. These precise, 4D, steep and banked curvilinearlanding approaches and climb outs are herein named curved trafficpatterns. Descending at an airspeed of 24 m/sec. the SkyQart travels onthis 106.4 m curved traffic pattern as its landing approach path. Ittravels this 106.4 m in only 5.6 seconds, reaching the point of landingtouch-down at a point just beyond the mid-point of the SkyNest pavement.The aircraft then consumes another 4.4 seconds by rapidly deceleratingon the pavement surface to the 7.6 m/sec taxiing speed at which speed itturns off the runway pavement to reach the position labeled as referencenumber 613, just 10 seconds after entering the SkyNest property atposition “O”. From the position at reference number 613, the aircraftcontinues taxiing at the speed of 7.6 m/sec to reach the position shownas reference number 617 along the arrival taxiway, i.e. Taxiway I, whichis shown in FIG. 14 as being adjacent to and parallel with the dock.From position 617, the aircraft continues taxiing for another 10 secondsat 7.6 m/sec to reach the position shown as reference number 619. Atposition 619, the SkyQart stops taxiing and proceeds to use itswheelmotors to precisely back into the aircraft docking station P at thedock, which it accomplishes in 10 seconds using its multi-sensor guidedprecision positioning system. The backing in and parking process rely onelectronic vehicle guidance using the SkyQart's wheelmotors along withthe active main landing gear ride height adjustment to consistentlyachieve a precise docking alignment. The precision positioning systemcan enable the SkyQart of QUAD to be rapidly parked in exactly theproperly aligned position at the dock of the SkyNest to enable it torapidly load and unload both SBPs and EPCs. This is accomplished using aprecision positioning system comprised of one or more of the followingguidance technologies: differential GPS, inertial navigation system(INS), line-following software, obstacle-avoiding video camera(s) visionsystem, auto-focus technologies of either active infrared or a verticaland horizontal auto-focusing CCD camera chip, a 4-beam convergentbio-medical He—Ne laser targeting a transponding receiver plate on thedock, and a capacitive proximity sensor for the final alignment to thedock surface. This combined parking alignment technology is importantand consistently aligns the parked SkyQart to within 2.0 mm of thecenter of the aircraft docking station so as to enable rapid loading andunloading of EPCs, as well as automated connection of the SkyQart to thedock's DC fast-charging port. Two slightly tapered pins in the dock areengaged into the two pin alignment holes in the aft face of theSkyQart's floorboard. The engagement of these pins maintains thenecessary alignment of the SkyQart to the dock. Automated heightadjustment of the active main landing gear of the SkyQart can also helpmaintain correct alignment of these pins during docking. Just prior tobacking in to its allotted aircraft docking station, the SkyQartautomatically opens its rear hatch door to prepare for charging andunloading of its EPC at the dock. Unloading will be followed immediatelyby boarding/reloading of another EPC. Deboarding and boarding are eachaccomplished in just 10 seconds, using standard 144.8 cm L×103.2 cm WEPCs, an example of which is shown in FIG. 14 as reference number 624.Several other identical EPCs are shown on the dock. Concurrent withthese 20 seconds that the SkyQart spends at the dock, a robot at theaircraft docking station can remove the SkyQart's spent standardswappable battery pack (SBP) and insert a freshly charged SBP intorollers that guide it precisely onto the drawer slides and into thebelly of the SkyQart, where its correct position, latching andelectrical integrity are automatically confirmed. Battery packreplacement need not occur at every docking, depending upon theparticular range of trips being flown by that SkyQart and the totalrange available per battery pack. As future battery energy densities andcharging rates improve and the average distance of QUAD flightsdiminishes, the frequency with which these robotic battery pack swapsoccur at the dock will diminish and the alternative automated chargingfrom the dock's DC fast-charging port can occur while the SkyQart isdocked. Just 20 seconds after the arriving SkyQart has completed itsdocking and has de-boarded and boarded anew, it departs from the dock,as shown by the SkyQart labeled as reference number 608 in FIG. 14. Thisexiting SkyQart proceeds in 10 seconds onto the taxiway that is adjacentto the runway pavement (Taxiway II), to reach the position shown asreference number 616 in FIG. 14, as it taxis toward the departure end ofthe pavement labeled as runway 14. From position 616, the SkyQartcontinues taxiing for 10 seconds on toward the end of the taxiway toreach the position shown as reference number 615. From position 615, theSkyQart taxis in less than 10 seconds into the position shown asreference number 600, which is the brake release take-off position ofrunway 14. Upon brake release at position 600, the SkyQart rapidlyaccelerates in 4.66 seconds to roll 43.9 m on wet pavement in no windconditions to reach the position shown as reference number 603, whileundergoing no more than 0.69 G's of acceleration with a jerk rate keptbelow 3.4 m/sec³ at all points during the take-off roll. From itslift-off at the position shown as reference number 603, the SkyQartclimbs steeply over a nominal ground surface distance of 104.5 m in 4.66seconds at an indicated airspeed of nominally 24 m/sec to reach, in justunder 10 seconds, the position shown as reference number 644 at location“C”, while achieving a height of 40 m at that location. At thislocation, the noise of the departing ESTOL SkyQart is nearlyimperceptible on the ground. The timing of the take-off is maximallystaggered with that of the landing aircraft so that a safe 4D separationis always maintained at the crossing point (labeled as “X” in FIG. 14)where the two curved flight paths cross above the pavement and at anyother crossing points on the SkyNest. The steep descent and climbgradients ensure that the flight paths over the taxiways remain wellabove the height of any taxiing SkyQart. The nominal 10-second cadenceof operations presented here is not to exclude from this inventionalternative cadences of as short as 7 seconds or as long 5 minutes,which will depend upon the maturation, location and regulations that areapplied to the QUAD system.

The SkyNest II

FIG. 15 depicts a nominal embodiment of a dual SkyNest II at which thecapacity of the standard SkyNest I is doubled by having two of thestandard SkyNest l's and their adjacent street amenities placed asmirror images, top and bottom in the drawing. All of the operationaldetails and subcomponents at the SkyNest II remain the same as thosedescribed with FIG. 14 for the SkyNest I except that the upper SkyNestis a mirror image of the lower SkyNest. The SkyNest II is shown in FIG.15 with two large but separate solar panel arrays, each one coveringboth a dock area and the adjacent street with dimensions of 167.6 m×48.8m, making 8175.5 sq m for each array. These are both shown in FIG. 15 aslarge crosshatched areas labeled as reference number 620. Referencenumbers 700 and 704 point to the combined public street and sidewalkareas that border each side of a SkyNest II as mirror images. Referencenumber 701 points to a vertically mirrored image of the SkyNest I ofFIG. 14, in which all of the same operational stages are shown and whichis placed above and adjacent to the standard SkyNest I, which itself islabeled as reference number 703. Reference number 702 points to therectangular double crosshatched area that is the required minimum bufferzone separator that is 12.2 m wide by 167.6 m long and that is placedbetween the two SkyNest I facilities to create the full SkyNest II inorder to ensure adequate separation of the aircraft that operateconcurrently on its parallel runways. As shown in FIG. 15, the SkyNestII occupies 2.76 ha of level land. Alternative embodiments of theSkyNest II are possible, including those of different size andoperational cadences, provided that they offer facilities that arecompatible with the extant QUAD system vehicles.

The SkyNest III (Tiny)

FIG. 16 depicts a nominal SkyNest III, in accordance with one embodimentof the present invention. This SkyNest is nominally only 99.1 m×61.0 mwhich is an area of 0.61 ha This SkyNest III can be smaller than thestandard SkyNest depicted in FIG. 14 because it is sited with itsborders adjacent to open space. Such open space may be either a shoreline, a wild land, a community greenbelt, a highly elevated area arounda building rooftop or other unpopulated area that is notnoise-sensitive. A greenbelt area may be an area of crops, grass, forestor golf course. A shore line may be along the surface of a lake,indolent river, bay or ocean. This open space provides an area overwhich there is a much greater tolerance for aircraft noise. It will beseen in FIG. 16 that the curved flight paths of both the arriving anddeparting SkyQarts at the SkyNest III are positioned over the open spacefor noise abatement purposes. The aircraft operations at the SkyNest IIIare somewhat different from those at the SkyNest I and, accordingly, aredenoted by different reference numbers according to their location onthe SkyNest III. For simplicity, these operations in FIG. 16 aredepicted for SkyQarts I and II but not with SkyQarts III. A SkyQart IIIis however shown parked inside the maintenance hangar at the SkyNestIII, and it is labeled as reference number 818. The details of thesidewalks, bicycle lanes and street adjacent to the SkyNest III areidentical to those detailed in FIG. 14. The labeled reference numbers inFIG. 16. In numerical order, are as follows: Reference number 800 pointsto a dashed line that represents the landing approach path of a SkyQartto the SkyNest III. Reference number 801 points to the outline of theSkyNest III land parcel, which is 99.1 m×61.0 m. These dimensions arethe standard for a SkyNest III and are the minimum size for theSkyQart's take-off and landing speed of 24 m/sec. These dimensions arechosen to also be large enough to ensure that the acceptable noisesphere of SkyQarts that are taking off consistently remains within thatSkyNest III's boundary with the community. Reference number 802 pointsto the jagged outline of the open undeveloped green-space or body ofwater that surrounds three sides of the SkyNest III. Reference number803 points to the left or port wingtip of a SkyQart I or II that is inthe take-off brake release position on the pavement. In order toefficiently share the use of the pavement, the touch-down of the landingSkyQart is sequenced to occur 10 seconds after the take-off brakerelease of a departing SkyQart. Reference number 804 points to thecrosshatched pavement surface of the SkyNest III. Reference number 805points to a double arrow that represents the portion of the pavementthat is typically used for ground roll after touchdown during a no-windSkyQart landing at the SkyNest III. The touchdown location, asrepresented by the left hand tip of that (805) double arrow in FIG. 16,is shown as being beyond the airpark fence at the left-hand side ofReference number 801, and is a location that affords adequate verticalclearance for the landing approach at the 2.44 m tall airpark deerfence. Reference number 806 points to the left wing of a departingSkyQart at the position on the pavement at which it would typically liftoff and begin its climb out if a no wind condition were in effect and ifthe maximum take-off acceleration of 0.8 G were achieved with GRACE.Reference number 807 points to the dotted line that represents thecurved path of the departing SkyQart's climb out after lifting off atthe SkyNest III. Reference number 808 points to the left or port wingtipof a landing SkyQart that is at the position at the end of the runwaypavement where it would turn off to begin taxiing to the dock. Referencenumber 809 points to one of the two optional runway clear zones at eachthe end of the SkyNest III runway. Reference number 810 points to theleft or port wingtip of a SkyQart that has turned off of the runway andis beginning to taxi on the taxiway toward an open aircraft dockingstation on the dock. Reference number 811 points to the right orstarboard wingtip of a SkyQart that is departing from the dock area totaxi onto the taxiway toward the take-off end of the pavement. Referencenumber 812 points to the left or port wingtip of a SkyQart that hastaxied into a hold-short position for the departure end of the pavement,where it is awaiting take-off. Reference number 813 points to the noseof a SkyQart that has completed its taxiing and come to a stop at aposition from which it can back in to a vacant aircraft docking stationat the dock. Reference number 814 points to the shared singular taxiwayof the SkyNest III. Reference number 815 points to the upper edge of thecoarsely crosshatched area that represents the rooftop solar panel arrayfor the SkyNest III. Reference number 816 points to the finercrosshatched area that represents the raised dock area of the SkyNestIII, which is 47 cm higher than the level of the pavement surface of therunway/taxiway. Reference number 817 points to the portion of theSkyNest III that fronts onto the sidewalk of the adjacent street andalong which the RDCs line up in order to load or off-load EPCs. Thestandard for autonomous operations calls for each step in the sequenceof operations at the various positions on the SkyNest III to requireonly 10 seconds or less. In FIG. 16, a SkyQart is shown making its steepfinal approach to landing at the SkyNest III along the curved dashedline that is reference number 800 in the upper left side of the drawing.The cadenced coordinated operations at SkyNests is the sequence ofstandard operations for completing the turnaround of that landingSkyQart and it will be slightly different at the SkyNest III than thecadenced coordinated operations at the SkyNest I or II. It will proceedas follows: At a nominal interoperable approach speed of 24 m/sec, thelanding SkyQart will touch down at a location marked by the tip of theleft-hand arrowhead of the double arrow shown as reference number 805 onthe landing portion of the pavement and will rapidly decelerate on thepavement surface, reference number 804, to reach its turn-off positionat reference number 808 where its taxiing speed will have slowed to just7.6 m/sec. From there, the SkyQart will continue to taxi at the nominaltaxiing speed of 7.6 m/sec to the position shown as reference number810. This interval of movement from its landing approach to reachposition 810 consumes 10 seconds. Then, in the next 10 seconds, thetaxiing SkyQart moves from its position at reference number 810 to aposition at reference number 814 where it stops momentarily and then, inthe next 10 seconds, backs up into the open aircraft docking station atthe dock, using its wheelmotors and precision positioning software topark in the exactly correct alignment with that station's batteryswapping/charging equipment. Position 814 will vary according to whichberth at the dock is unoccupied. The SkyQart will then de-board orunload its EPC in 10 seconds. It spends an additional 10 seconds in itsberth at the dock in order to complete the boarding or loading in of anewly laden EPC for the next flight. Concurrently with the 10 seconds ofde-boarding and 10 seconds of boarding time the SkyQart undergoesswapping of its spent SBP with a freshly charged SBP, providing it withanother 161 km+ of range. Once these steps are completed, the freshlyloaded SkyQart will leave its berth at the dock, as shown by the curvedarrow along the left or port wingtips of the sequence of three SkyQarts;the right wingtip on the middle one of these three SkyQarts is labeledas reference number 811. The SkyQart thus departing from the dock willbegin taxiing to reach, in just 10 seconds, the position labeled asreference number 812 at the departure end of the take-off pavement.During these 10 seconds of taxiing at 7.6 m/sec, the departing SkyQartmust share Taxiway I with any other arriving and/or departing SkyQartsthat are taxiing there. Thanks to the autonomous precision positioningusing on-board navigation systems, the sense and avoid systems, thenetworked situational awareness program and wheelmotor controllers ofthe autonomous control system, this sharing is reliably and routinelyaccomplished without conflict. Once it reaches position 812 and hascompleted its automated checklist for take-off, the SkyQart then willuse the next 10 seconds to taxi into the take-off brake releaseposition, which is labeled as reference number 803, on the pavement.From there, it will then rapidly accelerate on its take-off roll toreach position 806 in less than 5 seconds, where it will lift off thepavement and conduct over the next 5 seconds its curved climb-out path,reference number 807, to depart the SkyNest III in a curved trafficpattern at 24 m/sec. The movement from position that is reference number803 to departing the SkyNest consumes another 10 seconds. By thisidealized sequence then, the total turnaround time at this SkyNest IIIis summarized as follows: 10 seconds for approach, touch-down,deceleration and turning off the pavement; 10 seconds to taxi to a stopin front of an open berth at the dock; 10 seconds to precisely back intothe berth at the dock; 10 seconds to de-board or unload the EPC from theSkyQart at the dock; 10 seconds to board or load the laden EPC into theSkyQart at the dock; 10 seconds to taxi to the hold for take-offposition at 812, 10 seconds to taxi onto the brake release position onthe pavement; 10 seconds to complete the take-off and climb out to exitthe SkyNest III. This sequence enabling 80 seconds total turnaroundcycle time at the SkyNest III.

Note that the turnaround time (TAT) at the SkyNest III is shorter (80seconds) than for that using cadenced coordinated operations at thestandard SkyNest I shown in FIG. 14. This is due to the shorterdistances required for taxiing. However, the SkyNest ill has feweraircraft docking stations at its dock, eight in all, and, compared tothe sixteen aircraft docking stations at the SkyNest I, this reduces thebuffering effect of having several extra aircraft and aircraft dockingstations available at the SkyNest for resiliency in operationalsequences. The importance of the SkyNest III as one embodiment of thisinvention is that it provides an extreme example of high passengercapacity per acre of land parcel, which it achieves by taking advantageof siting at locations where noise sensitivities are reduced whileproximity is still very near where people live and work. In FIG. 16, theSkyNest III can be seen to include the same standardized core amenitiesas the standard SkyNest that is shown in FIG. 14. These include theLounge, Cargo Service. Hangar, ADA ramps, stairs to dock from sidewalk,crash cushion, EPCs, RDCs, as well as the adjacent street withshort-term curbside car parking spaces, bus and bicycle rack.Alternative embodiments of the SkyNest III are possible, including thoseof different size and operational cadences, provided that they offerfacilities that are compatible with the extant QUAD system vehicles.

The SkyNest IV (Bowl)

FIGS. 17 and 18 depict an embodiment of the SkyNest IV, in accordancewith the present invention. This SkyNest IV is designed to accommodateextremely short take-offs and landings in a direction appropriate toexisting current wind conditions. As such, it is a 360° circular airparkfacility. In addition, the pavement of the SkyNest IV is sloped so as togive its surface a bowl shape wherein the sloped sides of the bowlsubstantially enhance the acceleration and deceleration of the SkyQartsthat are landing or taking-off there. In effect, take-offs are madedownhill and landings are made uphill. The SkyNest IV can be seen toinclude the same standardized core amenities as the standard SkyNest Ithat is shown in FIG. 14. These include the Lounge, Cargo Service,Hangar. ADA ramps, stairs to dock from sidewalk, crash cushion, EPCs.RDCs, as well as the adjacent street with short-term curbside carparking spaces, bus and bicycle rack. In FIG. 17, reference number 900points to the street adjacent to the SkyNest IV, which is comprised ofthe same size and number of lanes and components as those depicted inFIG. 14. Reference number 901 points to the crosshatched area thatrepresents the dock surface of the SkyNest IV, which has the samestandard width, 7.5 m as that depicted for the SkyNests I, II and III.Reference number 902 points to a double arrow whose dimension representsthe 19.8 m radial dimension of the flat pavement area for taxiing thatextends from the top of the paved bowl to the outer edges of the SkyNestpavement. Reference number 903 points to a solid circle of 143.3 mdiameter that represents the upper outer rim of the nominal pavementbowl at the SkyNest IV. Reference number 904 points to the crosshatchedring that represents the pavement area on the upper outer slope of thebowl, which can be used for taxiing and whose radial dimension is 15.24m. Reference number 905 points to the bidirectional cart paths that arelocated at the outer borders of the above-ground version of the SkyNestIV wherein such paths are for the exclusive use by RDCs that need totravel to opposite sides of the SkyNest. Reference number 906 points tothe bidirectional spiral of concentric cart paths that, in thisembodiment, are located at the outer corners of the SkyNest IV propertyand that provide a path for RDCs to travel up and down the nominal 6.4 mheight difference between street level and the upper cart paths surfacesof the SkyNest IV. Reference number 907 points to one of theabove-ground SkyNest IV's four pedestrian stairwells that each occupy aspace of 8 feet by 16 feet and that enable passengers to move fromstreet level to the up-stairs dock level and vice versa. Note that thesestairwells are not depicted or needed on the dock area shown on the leftside of FIG. 17 because that left side dock area represents theembodiment of an excavated, street-level SkyNest IV. Reference number908 points to a top view of one of the five identical passengerelevators at the dock of the above-ground SkyNest IV. Each of these fivepassenger elevators is shown as being 8 feet square in planform. Thecombination of these five passenger elevators with the four pedestrianstairwells is sufficient, when supplemented by the deliveries of peopleand freight that occur by RDC, to fulfill the operational capacity ofthe dock on one side of a SkyNest IV. Alternative embodiments of thedock facilities at SkyNests to those presented herein, including thosethat provide more or fewer of these elevators and stairwells or thatprovide them in different locations on the dock, are nevertheless stillencompassed by this patent. Reference number 909 points to a solid linewith a directional arrow that represents a top view of the portion ofthe pavement that is used for the uphill landing roll of a SkyQart. Itwill be noted that there are two SkyQarts shown adjacent and on eitherside of the upper end of this landing roll, and each of these SkyQartsis depicted to have turned off of the landing pavement in order to taxito its intended dock. Reference number 910 points to an isolated arrowthat indicates the direction of the prevailing wind that, for thisdrawing, determines which runway directions will be used for thetake-off s and landings at the SkyNest IV shown in the drawing. It willbe noted in FIG. 17 that those runway directions are 30° apart,straddling the indicated wind direction arrow such that each runwaydirection is 15° different from that of the prevailing wind. Referencenumber 911 points to one of the two movable crash cushion carts that ispositioned at the end of the take-off pavement. It can be noted that theother crash cushion is positioned at the end of the landing pavement.Reference number 912 points to the exact and required standard touchdownpoint for landing for this wind condition at this embodiment of aSkyNest IV. This touchdown point is based upon the ground clearancerequirements for a SkyQart that approaches its landing touchdown whiledescending over the downhill portion of the bowl of a SkyNest IV. Forany runway chosen, this standard touchdown point will be 3.81 m beyondthe center of the bowl on the surface of the flat circular area that isconcentric at the bottom center of the bowl. Reference number 912 alsopoints to the beginning of a short thickly dashed line that is alignedwith the landing runway direction depicted in FIG. 9. The scaled lengthof this short thickly dashed line is 3.81 m. Reference number 913 pointsto one of the twelve thin dashed lines that represent some of thespoke-like alternative runway directions that could be usable at aSkyNest IV when favored by wind conditions. While the runway headings ofthese thin dashed lines are placed 300 apart for illustrative purposes,the actual runway headings used by the SkyQarts operating at a SkyNestIV could be any compass headings that are suitably oriented into theprevailing wind. Reference number 914 points to a circular line thatoutlines the nominal 15.24 m diameter circle of flat pavement surfacethat lies concentric at the bottom center of the bowl at a SkyNest IV.This outline is for illustrative purposes only because the actualtransition from the flat bottom of the bowl to its up-sloped sides is,in reality, not built as a sharp angle change but is instead a gentletransition with a fillet radius of 12.2 m. Reference number 915 pointsto a curved thickly dotted line whose arc depicts the climb-outtrajectory of the SkyQart, beginning at the center of the bowl. This arcis 100.3 m long in the no-wind condition and it begins after the SkyQarthas completed its initial climb aligned with the runway heading fromliftoff to the center of the bowl, a segment shown by a straight, thinlydotted line of 29.0 m length and separately labeled as reference number924. In FIG. 18, reference number 916 points to the tip of the curvedarrow that represents a side view of the standard climb profile of aSkyQart in the no-wind condition and that reaches a height of 40 m abovethe bottom of the bowl. The climb profile shown by reference number 916is not conducted in a banked turn but is instead entirely flown whilemaintaining the heading of the take-off pavement. Reference number 917points to a side view of the climb profile of a SkyQart in a 16 km/hrheadwind condition, showing the larger ground clearances that result.Reference number 918 points to a side view of the surface of the dockthat is used at an excavated type of SkyNest IV. The surface of thisdock as shown is the standard 47 cm above the level of the pavementsurface of the aircraft parking area adjacent to the dock, which is thestandard dock height used at all other SkyNests. The width of thesurface of this dock is the SkyNest standard of 7.5 m. The dock surfaceis also shown to be the nominal 129.5 cm above the bottom of theunder-dock service bay that contains the robotic battery swap equipment.Reference number 919 points to a side view of the street level adjacentto the sidewalk at an excavated type of SkyNest IV. This street level isshown adjoining a sidewalk curb that is 15.24 cm tall. The sidewalkadjacent to the street level adjoins the dock at the SkyNest and itssidewalk surface is 47 cm below the height of the dock surface.Reference number 920 points to a side view of the point of the standardlanding touchdown at a SkyNest IV. Reference number 921 points to a sideview of the point that is the center of the bottom of the bowl where thedashed line represents the 15.24 m diameter circular flat area centeredat that point. This center at 921 can be seen to coincide with thecenter of the bowl above in the FIG. 17 view of the SkyNest IV.Reference number 922 points to a SkyQart whose nosewheel is positionedon the level pavement at the top of the bowl that is the brake releasepoint for take-off on the active runway. Reference number 923 points toa solid line with arrow that indicates a top view of the nominal 42.7 mtake-off distance of a SkyQart in the no-wind condition. Referencenumber 924 indicates a thinly dotted line that represents the 29.0 mdistance traveled by the SkyQart is its straight-ahead initial climbfrom its point of lift off to the center of the bowl. The intersectionof the trajectories of departing and arriving SkyQarts at the center ofthe bowl can be safely managed by staggering the timing of their flightsas 4D trajectories. Reference number 925 indicates a top view of adashed line that depicts the curved no-wind landing approach of theSkyQart. It will be noted that this approach comes to align with thelanding runway heading and that it passes through the center of thebowl, continuing 3.81 m beyond that center to the standard point oftouchdown shown by reference number 912. Reference number 926 points tothe 2.44 m×4.88 m cargo/freight/vehicle elevator that is inside theCargo Service Building and that lifts cargo from the street-level truckdock below to the dock level above at an above-ground type of SkyNestIV. In FIG. 18, reference number 927 points to a point that is 40 mabove the bottom of the bowl and is the topmost point of a side view ofthe landing approach profile of a SkyQart in a 16 km/hr headwindcondition. Reference number 928 points to a point that is 40 m above thebottom of the bowl and is the topmost point of a side view of thelanding approach profile of a SkyQart in a no-wind condition. It will benoted that both 927 and 928 have the same touchdown point, but that the927 approach in the wind offers substantially larger ground clearances.Reference number 929 points to a tiny double arrow that indicates theworst-case clearance of 4.15 m above the tail section of a taxiingSkyQart for the case of a no-wind landing approach. In FIG. 18,reference number 922 also points to a side view of a SkyQart that is atthe brake release position for take-off. Reference number 931 points toa nominal 45.7 m wide solar panel array that is 12.5 m above the streetarea and 6.1 m above the level taxiing surface of the SkyNest TV.Reference number 932 points to a side view of the surface of the RDCoperations area adjacent to the dock at an above-ground SkyNest IV.Reference number 933 points to a side view of a crosshatched area underthe surface of an above-ground SkyNest IV that represents the buildingarea for potential commercial and housing uses. Reference number 934points to a side view of the truck dock that is a nominal 1.22 m abovestreet level at the above-ground type of SkyNest IV. Reference number935 points to a side view of the liftoff point for a take-off made intoa 16 km/hr headwind, where the take-off distance is only 27.1 m.Reference number 936 points to a side view of the liftoff point for astandard take-off in no wind, where the ground roll is 42.7 m.Alternative embodiments of the SkyNest IV are possible, including thoseof different size and operational cadences, provided that they offerfacilities that are compatible with the extant QUAD system vehicles.

The SkyNest V (Rooftop)

FIG. 19 depicts a simplified view of a standard minimum-sized rooftopSkyNest V, in accordance with one embodiment of the present invention.This embodiment depicts the standard SkyNest V with its minimumdimensions, which are predicated on the extremely short take-off andlanding (ESTOL) performance capabilities of the SkyQart. Other, larger,alternative embodiments of this standard minimum SkyNest V can occur inorder to fit varying sizes of existing building rooftops and these arealso encompassed by this patent. The SkyNest V is anticipated to providehigh-proximity QUAD services to metro centers, urban canyon areas andlarge hub airport terminals where the built environment precludesfinding a larger land parcel size for a surface SkyNest and/or wherethere is no proximate shoreline or greenbelt for siting of a smallerSkyNest III. The SkyNest V can be sited on the rooftop of largemulti-level parking garages that are typically adjacent to many majorairline hub airports and amusement parks. These hub airport SkyNest Vswould provide QUAD services for airline travelers and thereby offer themmajor time savings compared to their trips using ground transportationto and from the hub airports. Some SkyNest Vs may be built atopmulti-story office or residential buildings. In FIG. 19, referencenumber 1000 points to the surface of the ground floor of the SkyNest V,which is nominally considered to be at street level. Reference number1001 points to a vertical arrow that depicts the 60 m height abovestreet level of the pavement surfaces at this SkyNest V. This height mayvary depending upon the building's size, surroundings and ambient noiselevel. Reference number 1002 points to one of the four corner pillars ofthe SkyNest V building. These pillars may be of varying size and maycontain high-speed passenger and/or freight elevators that move peopleand goods to and from the SkyNest V dock and the ground floor. It shouldbe noted that there is normally no need for pedestrian access to therooftop pavement surfaces at a SkyNest V, since all passenger-boardingand de-boarding occurs at the dock area on the floor below the rooftop.It is however possible to have a rooftop SkyNest whose passenger dock isincluded on the rooftop; in which case it would closely resemble thelayout of a SkyNest III as shown in FIG. 16. Reference number 1003points to the bottom edge of the dock service bay in which batteryswapping occurs. Reference number 1004 points to a rectilinear box thatconceptually represents one of several loaded EPCs that would beoperating on the dock area. Reference number 1005 points to the surfaceof the dock area, a surface that is the standard 47 cm above the floorof the adjacent taxiing ramp area, and is the same dock height used atall other types of SkyNests. Reference number 1006 points to theperimeter safety fence or wall that surrounds the rooftop pavement andramp area. A similar perimeter safety fence or wall would surround theouter edges of the dock on the lower level, but this is not depicted inFIG. 19 in order to clarify other features. A horizontal, life-savingperimeter net, similar to that used on the Golden Gate Bridge, wouldlikely be placed outside the perimeter safety fence on both the rooftopand dock levels of the SkyNest V, but for the sake of simplicity andclarity in depicting other features, that perimeter net is not depictedin FIG. 19. Reference number 1007 points to the surface of the rooftoppavement area of the SkyNest V, whose area is nominally 99.1 m×99.1 mmaking an area of 0.98 ha. Reference number 1008 points to the end of asolid line that depicts the direction (arrow) and the 38.7 m length of a0.8G GRACE take-off distance of a SkyQart at the SkyNest V. Referencenumber 1009 points to the location of landing touchdown at the end of adashed line that depicts the direction (arrow) and the 43.9 m length ofa 0.8G GRACE landing ground roll of a SkyQart at the SkyNest V in thecase of the wind direction shown by the dotted line arrow and labeled asreference number 101 II. The location of landing touchdown as shown is29.0 m beyond the intersection of the landing path with the outer edgeof the rooftop. This 29.0 m is the nominal distance needed to complete a3-meter final descent with GRACE when flying at an airspeed of 24 m/sec.This 43.9 m length of ground roll is the nominal distance needed in zerowind conditions for the SkyQart to decelerate with GRACE at a maximum of0.8G while using regenerative braking and reverse propeller thrust fromits touchdown speed of 24 m/sec to its taxiing/turn off taxiing speed of7.6 m/sec. Reference number 1010 points to the surface of the downhillexit ramp that allows the arriving SkyQart to taxi to the dock that islocated on the lower level that is below the rooftop pavement area ofthe SkyNest V. Reference number 1011 points to the dotted arrow thatdepicts the wind direction on which are based the take-off and landingdirections and the positioning of the movable crash cushion in thisdepiction of the SkyNest V. Reference number 1012 points to the portablecrash cushion placed in the position appropriate to the wind directionillustrated by reference number 1011. The crash cushion is designed toslide 1.1 m to full stop in the event of a SkyQart impacting it at 20m/sec. Accordingly, and to maximize runway length, the crash cushion isshown positioned with its impact surface inboard of the outer edge ofthe rooftop pavement. Reference number 1013 points to the surface of thetaxiway ramp area that serves the dock area on the lower level of theSkyNest V, one floor below the rooftop pavement surface. Referencenumber 1014 points to the uphill entry ramp that allows the departingSkyQart to taxi from the dock that is located on the lower level thenceupward to the rooftop pavement area of the SkyNest V. Reference number1015 points to the large 14-story building that serves as a supportpillar for the reference number 1014 uphill ramp. A similar 14-storybuilding is shown at the rear of the SkyNest V, supporting the downhillramp that is labeled as reference number 1010. These buildings may houseoffices or residences and therefore may not considered to be part of theSkyNest V land parcel footprint. Alternatively, the reference numbers1010 and 1014 may be structured as gusseted, cantilevered ramps that donot have a building supporting them. Reference number 1016 points to alarge surface that represents one of the many other floors that couldpotentially fit into the structure that supports the rooftop SkyNest V.In FIG. 19, these additional floors would number 13, if the separationbetween each floor level were the nominal standard height of 4.27 m.However, in other buildings whose rooftops harbored SkyNest Vs, theselower floors could vary widely in number from as few as two to as manyas one hundred or more and could be used for car parking, housing,offices, warehousing or retail spaces.

Fast Flaps System

FIG. 20 illustrates the Fast-Flaps System used on SkyQart aircraft inorder to enable their ESTOL performance and aerial agility, inaccordance with one embodiment of the present invention. The fast flapsystem in this embodiment is a double-slotted flap system in which thetwo flap segments, forward and rear, are shown in both their retractedand fully extended positions. The forward flap segment nests above thelarger rear flap segment, and each of them has a sturdy vertical strutfirmly attached to its leading edge and internal main spar. Thesevertical struts, which may be multiple along the flap's span and mayvary from two to four struts per flap segment, extend downwardunderneath the wing from the flap segment to their attachment at thatflap segment's hinge pin that is located on a large external hinge fin.Each flap segment has its own separate hinge pin and these hinge pinsare located on a shared hinge fin. The exact locations of these hingepins on the hinge fin are critical to the operation of the fast flapsystem. These hinge pin locations determine the geometry of theextension of the flap segments and, thereby, the lift-enhancingperformance of the flap system. These hinge pin locations are accuratelydrawn in FIG. 20 so as to produce the correct gap and overlap of thefully extended flap segments. In order to minimize leakage drag, thefully retracted flap segments nest snugly inside the rear flap coveportion of the main wing airfoil within minimal gaps between them andthe external wing surfaces. The fast-flap name is applied because theseflaps are specially designed to fully retract in less than 0.5 secondsat the moment of touch-down on landing of the SkyQart. In FIG. 20,reference number 1100 in this embodiment of the fast flap system pointsto the forward upper surface outline of the main wing's GAW2 airfoil asit exists at the root of the wing flaps. Reference number 1101 points toa horizontal double arrow that depicts the nominal 142.3 cm chord lengthof the main wing at the inboard flap root. Reference number 1102 pointsto the forward face of the main wing spar. Reference number 1103 pointsto the space that is the mid-wing bay between the main spar and rearspar. The mid-wing bay is the location for the pancake motor thatactuates the fast flap system. Reference number 1104 points to the largeunderwing hinge fin that provides the hinge pins to which attach theflap hinge struts of each flap segment. Reference number 1105 points tothe front face of the rear spar of the main wing. Reference number 1106points to the forward portion of the empty space known as the flap cove.The flap cove is behind the rear spar of the main wing and it providesthe space into which the flap segments nest when fully retracted.Reference number 1107 points to the center point of the bolt hole thatattaches the pushrod from the motor to the nose of the forward flapsegment. Reference number 1108 points to the interior of the proprietaryairfoil of the forward flap segment. Reference number 1109 points to theflap hinge strut of the forward flap segment, which connects it to thereference number 1104 hinge fin at the hinge pin labeled as referencenumber 1124. Reference number 1110 points to the upper surface of thetrailing edge of the main wing's flap cove. Reference number 1111 pointsto a dashed line double arrow that depicts the 46.5 cm length of thechord of the rear flap segment. Reference number 1112 points to a solidline double arrow that depicts the 18.64 cm length portion of the uppersurface of the rear flap segment that is exposed aft of the uppertrailing edge of the flap cove (reference number 1110). Reference number1113 points to a small horizontal solid double arrow that depicts the26.8 mm length of overlap between the forward flap segment and thetrailing edge of the flap cove. Reference number 1114 points to thesmall vertical solid double arrow that depicts the 38.1 mm air gapbetween the extended forward flap segment and the underside of thetrailing edge of the flap cove. Reference number 1115 points to thetrailing edge of the rear flap segment in its fully retracted position.Reference number 1116 points to a pair of thin solid lines that areseparated by the 1.07 mm distance that is the overlap between theforward and rear flap segments when both are fully extended. Referencenumber 1117 points to a small, nearly vertical solid double arrow thatdepicts the 32.5 mm length of the air gap between the forward and rearflap segments when both are in their fully extended positions. Referencenumber 1118 points to the center point of the bolt hole that attachesthe pushrod from the motor to the nose of the rear flap segment.Reference number 1119 points to the interior of the proprietary airfoilof the rear flap segment. Reference number 1120 points to the large flaphinge strut of the rear flap segment. Reference number 1121 points tothe solid line double arrow that is the curved arc of 56° that depictsthe range of travel of the rear flap segment from its retracted to itsfully extended position. Reference number 1122 points to the solid linedouble arrow that is the curved arc of 34° that depicts the range oftravel of the forward flap segment from its retracted to its fullyextended position. Reference number 1123 points to the center axis ofthe hinge pin for the rear flap segment. Reference number 1124 points tothe center axis of the hinge pin for the forward flap segment. Referencenumber 1125 points to a long, solid line double arrow that depicts the172 cm chord of the wing with its flaps fully extended.

Active Main Landing Gear

FIGS. 21 and 22 illustrate views of the SkyQart's Active Main LandingGear system, in accordance with one embodiment of the present invention.The active main landing gear is a concept and process invention thatprovides a long-travel main landing gear that can gracefully absorb ahigh rate of sink rate upon landing and can autonomously provide veryrapid and precise changes in ride height and, thereby, change theSkyQart's pitch attitude on the ground. The changes in ride heightenable two key capabilities required in QUAD. The first is thecapability to set the ride height to match the height of the loadingdock floor. The second is the capability to rapidly rotate the aircraftinto a nose-up attitude at the moment during the take-off roll when suchrotation is needed for lift-off. The active main landing gearaccomplishes the change in ride height by moving the main landing gear'srigid lever arm that is inside the Axisymmetric Fuselage Pod (AFP). Apowerful motor that uses the energy in the SkyQart's battery packactively moves this lever arm by exactly the appropriate amount, andthis active main landing gear motor's movements are controlled by asoftware application that accurately, instantly, continuously andautomatically senses the appropriate pitch attitude, sink rate and rideheight of the aircraft. The actuating mechanism by which the active mainlanding gear motor(s) control(s) the movement of the main landing gear'slever arm may use different actuator devices in different embodimentswhile still being included in this patent's concept and process²⁷. Oneembodiment is by a special design of linear motor that exerts directcontrol of the arm's position. Another is by a rotary motor that spinsthe shaft of a ball-screw or jack-screw, which, in turn, translates themotion of the spinning shaft to linear motion in order to move thelanding gear's lever arm the appropriate distance. A third embodimentcould use an actuator mechanism that is a hydraulic cylinder whoselength and compression resistance is rapidly varied to the appropriatelevel by an electro-hydraulic pump. Yet another embodiment may use amagnetorheological damper to modulate the position of the landing gear'slever arm. The active main landing gear has three main workingpositions. One is for the cruise flight condition, in which theswept-back main landing gear leg and its airfoil-shaped cover fairingare aligned with the free-stream airflow in flight to reduce drag. Thecruise flight working position is at the top of the range of motion ofthe active main landing gear. The second working position is the dockingposition, for docking the SkyQart. This docking position is one in whichthe main landing gear leg and lever arm are rotated from their cruiseflight position downward 14.6° around the center of their trunnion. Thisdocking position aligns the ride height of the SkyQart so that its cabinfloorboard height exactly matches the standard 47 cm height of theloading dock. The third working position is the fully dangle downposition of highest drag, called the landing approach position, which isused during a SkyQart's steep final approach to landing. The landingapproach position is one in which the main landing gear leg and leverarm are rotated 49° downward from the docking position, making 63.6° oftotal rotation downward from the cruise flight position. The landingapproach position of the main landing gear provides a nominal totallanding gear travel in jounce of 65.0 cm for absorbing the landingimpact upon touchdown. There are two additional working positions that,for clarity, are not shown in FIG. 22. The first of these is thenose-down pitch attitude position that is used during the initialportion of the take-off roll in order to enhance down-force on the tiresto enhance their traction on the pavement and to prevent a wheelie. Thenose-down pitch attitude position is also routinely used to minimizeunwanted lift during the portion of the landing ground roll just aftercompleting the full landing gear jounce after touchdown. The nose-downpitch attitude is also used during the time that a SkyQart is parkedaway from a dock. The second of the additional positions not depicted inFIG. 22 is the momentary position in which the main landing gearabruptly retracts enough to produce a nose-up pitch attitude of theSkyQart to suddenly increase its lift at the exact moment when itreaches its preferred lift-off speed of 24 m/sec during its take-offroll. In FIG. 21, reference number 211 points to a frontal view of thelever arm, shown in crosshatch, that moves the active main landing gearthrough its range of motion. This lever arm is rigidly attached to thetransverse trunnion bar, shown in frontal view as crosshatched andlabeled as reference number 218, whose rotation in the two main landinggear pillow block bearings provides the swing axis of the active mainlanding gear. Reference number 1201 points to a frontal view of ahorizontal line that is 47 cm above the ground level and that representsthe surface level of the loading dock which is level with the cabinfloorboard of the SkyQart when its landing gear are in the dockingposition, as shown. Reference number 1202 points to a double arrow whoselength represents the 47 cm height of the dock at a SkyNest. Referencenumber 1203 points to a frontal view of a horizontal line thatrepresents the ground or surface level on which the tires of the SkyQartare resting when in the docking position. Reference number 213 points toa frontal view of the right main landing gear leg. Reference number 214points to a frontal view of the triangular starboard pillow blockbearing whose structure is integrated into the AFP and that, along withthe port side pillow block bearing, bears and spreads the loads impartedby the main landing gear's transverse trunnion bar. Reference number 218points to a frontal view of the 2.54 cm diameter transverse trunnion barthat joins the port and starboard main landing gear legs. Referencenumber 1207 points to a frontal view of the outline of the nose geartire. Reference number 1208 points to a side view of the main wingairfoil at the midline of the SkyQart, showing its position relative tothe nose and main gear tire contact patches. Reference number 207 pointsto the side view of the midline mono-strut that attaches the main wingto the AFP. The empennage is omitted from FIG. 20 for simplicity.Reference number 1210 points to the line that depicts the seam in theAFP that can open to separate its rear hatch from its forward portionduring loading and unloading operations at the dock. Reference number1211 points to the pushrod that connects the powered actuator to thereference number 211 crosshatched main landing gear lever arm, which armis shown in its dangle down, landing approach position. Reference number213 points to a side view of the finely crosshatched main landing gearleg in its cruise flight position. Reference number 212 points to theaft edge of the starboard main landing gear tire of nominal 40.64 cmdiameter, which, like its identical mate the port or left main landinggear tire, is mounted on a powerful wheelmotor whose exact rotationalposition, RPM and power are controlled so as to provide take-offacceleration, regenerative braking on landing, as well as preciselyguided trajectories for taxiing, parking and docking. This landing geartire is shown in its retracted, cruise flight position and a partialoutline of its enclosing wheel fairing is shown behind it for reference.Reference number 1215 points to a double arrow whose length of 65.0 cmdepicts the full range of jounce travel of the main landing gear tire.Reference number 1216 points to a side view of a line that depicts thelevel of the pavement during initial touchdown of the SkyQart duringlanding. Reference number 213 points to a side view of the right mainlanding gear leg in its docking position. Reference number 1218 pointsto a side view of the dashed line that outlines the shape of the wheelfairing of the crosshatched main landing gear tire when the main landinggear is in its dangle down landing approach position. Note that the nosetire position is not shown for this touchdown line since it could be atany of several positions. Reference number 1219 points to a side view ofa line that depicts the ground or surface level of the pavement as wouldoccur when the SkyQart is docked. Reference number 1220 points to adouble arrow of 21.6 cm length that depicts the nominal ground clearanceof the belly of the AFP. Reference number 1221 points to a side view ofone outline of the active main landing gear's powered actuator (ofwhatever type used) that moves the main landing gear lever arm toposition the landing gear. The powered actuator shown has the appearanceof a hydraulic ram, but many other types of actuator may be used inother embodiments. Reference number 1222 points to a side view of theforward pivot axis for the landing gear powered actuator. The locationof this pivot may vary in different embodiments of the SkyQart. Thispivot is located at the apex of the large load-spreading gusset that isstructurally integrated into the AFP. Reference number 1223 points to aside view of the outline of that large load-spreading gusset. Referencenumber 1224 points to a side view of the undersurface of the floorboardof the cabin in the SkyQart.

The Ultra-quiet Propeller

FIGS. 23 and 24 depict a nominal embodiment of the ultra-quietpropeller. The ultra-quiet propeller is an important component to thisinvention. It is a seven-bladed propeller of a nominal 3.05 m diameterthat is used on the embodiments of SkyQarts depicted in this inventionand this is shown in frontal view in FIG. 23, along with a separatefrontal view in FIG. 24 of its central controllable pitch propeller hub.These propellers are of the design used in the author's existing patentnumber U.S. Ser. No. 10/415,581 B1. These propellers accordinglyincorporate blades of high-aspect ratio with laminar flow airfoilsections tailored by CFD to minimize spanwise flow and to havedeliberate blade strengthening increases at Fibonacci intervals in orderto dampen harmonic blade vibrations. These blades also incorporate thatpropeller patent's special blade angles near their tip that, in normaltake-off operation, produce a small amount of reverse thrust so as toreduce or eliminate their blade tip vortex and the noise attendantthereto. The propeller shown in FIG. 23 has seven blades with equalspacing between blades. This propeller is shown with zero blade twist inorder to better depict its planform shape. Reference number 1300 pointsto the blade tip. Reference number 1301 points to the trailing edge ofthe blade at its 0.75R or 75% blade station. Reference number 1302points to the innermost airfoil of the blade where it exits thestreamlined spinner. Reference number 1303 points to the central thrustaxis of the propeller. Reference number 1304 points to the outer limitof the round neck of the propeller blade shank that fits inside the hub.Note that the round neck of each blade is shown here with a round nub atits inner end and without its blade retention clamp. Reference number221 points to a frontal view of the outer circumference of thestreamlined spinner that encloses the hub and the innermost portions ofthe blade neck and its fillet transition to the innermost blade airfoil.The generic, 7-bladed, controllable pitch propeller hub is depictedbelow the propeller blades in FIG. 24. Reference number 1306 points toone of the seven propeller blade retention clamps located inside thishub. Each blade retention clamp typically has a cam-following pin on itsinner surface, shown as reference number 1308 in FIG. 24. Eachcam-following pin in the hub can be moved an equal amount by a smallmotor inside the hub (not shown) so as to identically rotate eachpropeller blade to the blade angle that is appropriate for the desiredthrust and RPM. Reference number 1307 points to the propeller hub'scentral round propeller mounting flange, which attaches the hub to thepropulsor unit (electric motor). The six equally spaced mountingbolt-holes in this flange are omitted for clarity. Alternativeembodiments of ultra-quiet propellers could be used in the QUAD system,if they fulfill the ultra-quiet and efficiency needs of the QUAD system.

The Electric Payload Cart (EPC)

FIGS. 25, 26, 27 and 28 depict a standard embodiment of the ElectricPayload Cart (EPC) and its details. The EPC is an important component tothis invention. It is the device that enables the very short turnaroundtime (TAT) for loading and unloading SkyQarts at the docks of the QUADsystem. With its standard embodiment of the seat-latching rails andlatching system, each EPC can provide attachments with which to pre-loadvarious types of payload and then can be autonomously positioned on thedock surface in a position close by to where the next SkyQart will dockand open its rear hatch. Once the SkyQart's rear hatch is fully open,the EPC can autonomously and rapidly roll into the SkyQart's cabin andbe automatically pin-latched securely to its interior structure. Once solatched, the rear hatch is closed and the SkyQart is ready fordeparture. In FIG. 25, reference number 1400 points to a frontal view ofthe EPC's port rear wheel housing, which supports the axle bolt andencloses both the rear tire and its wheelmotor. Reference number 1401points to a frontal view that shows the cross-section of the EPC's portoutboard seat-latching track. It will be seen that there are a total ofsix separate but parallel seat latching tracks on the top surface of theEPC. Reference number 1402 points to a frontal view of one of the 6.86mm diameter receptacle holes in the side of the surface deck of the EPC.The EPC has two separate sets of four identical holes arranged in alinear array with equal spacing along each of its sidewalls. Each ofthese four receptacle holes are 12.7 mm deep and they are spaced 25.4 mmapart. These holes serve as receptacles for the four, separate,solenoid-operated latching pins that fixate the sides of the EPC to theinterior of the AFP and to the surface deck of the RDC. Reference number1403 points to a frontal view of the bottom edge of the port rearwheelmotor housing. In FIG. 27, reference number 1404 points to a topview of the 6.35 mm diameter latching pin that is inside the latchingsolenoid on the port side of the EPC. There are a total of fouridentical pins and solenoids shown in FIG. 27. FIG. 26 depicts oneembodiment of a payload-holding device. Reference number 1405 points toa frontal view of the strut of such a payload-holding device. This typeof strut may be part of any of a variety of payload-holding devices,including a seat, a cargo bin, a latching rack, etc. This strut is seento contain a tiny roller and to terminate in a claw shape that wrapsaround the rail of the seat-latching track below it. Reference number1406 points to a frontal view of the edge of a rectangular block-likebody of the solenoid whose vertical pin latches the payload-holdingdevice to the rail of the seat-latching track. Reference number 1407points to a frontal view of the tiny roller that is enclosed in theterminal claw shape of the strut shown as reference number 1405. Thistiny roller helps to ease movement of payload-holding devices along theseat latching tracks when they are re-positioned in order to adjust thecenter of gravity of a payload. Reference number 1408 points to thehexagonal head bolt that serves as the axle for the tiny roller that isreference number 1407. Reference number 1409 points to a frontal view ofthe crosshatched outline of the 6.86 mm diameter vertical hole in thecenterline of the rail of the seat-latching track. Reference number 1410points to a frontal view of the lateral edge of the seat-latching track,showing the outline of its shape including its central rail. Referencenumber 1411 points to a side view of the hexagonal nut that secures thebolt that is reference number 1408, into position and allows it tocompress the bushing that is reference number 1415 for the tiny roller.In FIG. 28, reference number 1412 points to a side view of the pull-ringthat can be used to manually disengage the normally-extended solenoidlatching pin. This pull ring, when pulled to disengage, can be latchedinto that disengaged position. Reference number 1413 in FIG. 28 pointsto a side view of one of the many 6.86 mm holes in the top of thecentral rail of the seat-latching track. Reference number 1414 points toa side view of the vertical solenoid latching pin that secures thepayload-holding device to the seat-latching track. Reference number 1415points to a side view of the inner surface of the hollow shaft bushingfor the tiny roller. In FIG. 25, reference number 1416 points to afrontal view of the bottom of the starboard rear tire of the EPC.Reference number 1417 points to a frontal view of the bottom surface ofthe floorboard of the EPC. Reference number 1418 points to a frontalview of the inner seat-latching track, which extends the full length ofthe EPC. Reference number 1419 points to a frontal view of the batterypack of the EPC. In FIG. 27, reference number 1420 points to a top viewof the swivel axis of the right or starboard front castoring wheel.There is an identical left or port front castoring wheel shown in FIG.27. Reference number 1421 points to a top view of the front edge of thefloorboard of the EPC. Reference number 1422 points to a top view of thecenterline rail of the starboard inner seat-latching track. Referencenumber 1423 points to a double arrow that denotes the 30.5 cmcenter-to-center distance from the starboard inner seat-latching trackto the port inner seat-latching track. Reference number 1424 points to atop view of the centerline rail of the starboard middle seat-latchingtrack. Reference number 1425 points to a double arrow that denotes the8.9 cm center-to-center distance from the starboard inner seat-latchingtrack to the starboard middle seat-latching track. Reference number 1426points to a top view of the centerline rail of the starboard outerseat-latching track. Reference number 1427 points to a double arrow thatdenotes the 25.4 cm center-to-center distance from the starboard middleseat-latching track to the starboard outer seat-latching track.Reference number 1428 points to a top view of the center of the 228.2 cmarm length from the e.g. datum at the nose of the AFP, which is thenormal arm length at which the seated crew weight applies when the EPCis pin-latched, as shown in FIG. 27, at the rear-most of its fourlatching pin holes. Reference number 1429 points to a top view of thenavigation module that sits atop the rear portion of the floorboard ofthe EPC. Reference number 1430 points to a top view of the battery packof the EPC. Reference number 1431 points to a top view of the rightstarboard axle bolt of the EPC. Alternative embodiments of the EPC couldbe used in the QUAD system, provided that their size and function arecompatible with the operation of the other vehicles in the system.

The EPC Payloads

FIGS. 29, 30, 31 and 32 depict some of the common types of payload thatthe standard EPC can carry, showing 3-view layered drawings of how suchpayloads would fit onto the EPC and inside the AFP of the SkyQart. Thesecommon payloads include passengers, baggage, cargo and buildingmaterials. These drawings are sample embodiments and do not constrainother possible payloads or loading geometries from being carried in theQUAD system. The cargo axisymmetric fuselage pod is shown in FIG. 32,and its use requires that the EPC be pin-latched into the SkyQart at aposition nominally 25.4 cm further aft from the standard solenoidlatching pin locations. In FIG. 27, reference number 1500 points to aside view of the forward baggage compartment in a two-seat EPC/SkyQartconfiguration. Reference number 1501 points to a side view of theforward surface of the passenger seat support bracket, which pin-latchesto the seat latching tracks of the EPC. Reference number 1502 points toa side view of the seatback of the passenger seat in its normalnon-reclined position. This same seatback is also shown in side view asa dotted outline in FIG. 27 as one that is tilted back 30°, which is itsfully reclined position. Reference number 1503 points to a side view ofthe rear baggage compartment in its normal non-reclined position. Theoutline of this same baggage compartment is also shown tilted back 34°,as it would be if the seatback were fully reclined. Reference number1504 points to a side view of the space, shown in coarse crosshatch,normally occupied by removable flotation module #1. Reference number1505 points to a side view of the space, shown in finer crosshatch andextending 96.5 cm aft of the rear hatchline, normally occupied byremovable flotation module #2. In FIG. 28, reference number 1506 pointsto a side view of the aft face of the nosegear bulkhead at FS 68.6 cm,where the diameter of the AFP is 87.8 cm. Reference number 1507 pointsto a side view of the forward portion of the front seat support bracket,shown in crosshatch, as would occur in the case of an EPC with athree-seat payload. Reference number 1508 points to a side view of theforward portion of the rear seat support bracket, shown in crosshatch,as would occur in the case of an EPC with a three-seat payload.Reference number 1509 points to a side view of the rear hatchline wherethe rear hatch opens and separates from the forward portion of the AFP.In FIG. 29, reference number 1510 points to a side view of the 63.5 cmL×63.5 cm H×63.5 cm W forward cargo extension bin, shown in horizontalcrosshatch at its nominal position cantilevered from the front side ofthe main cargo box. The interior space of reference number 1510extension cargo bin is contiguous with that of reference numbers 1513and 1514. Reference number 1511 points to a double-ended arrow thatdepicts the 2.44 m dimension that exists inside the three combined cargobins (reference numbers 1510, 1513 and 1514) to enable them together tocarry packages up to 2.44 m in length. Reference number 1512 points to aside view of the aft surface of one of the large central Main CargoBin's forward support brackets, shown in fine horizontal crosshatch.Reference number 1512 is one of four such support brackets, two forwardand two rear, each of which pin-latches to the seat latching tracks ofthe EPC to secure the cargo bin(s) to it. Reference number 1513 pointsto a side view of the nominal 121.9 cm L×91.44 cm H×106.7 cm W centralMain Cargo Bin, shown in medium-sized grain horizontal crosshatch.Reference number 1514 points to a side view of the 63.5 cm L×63.5 cmH×63.5 cm W rear extension cargo bin, shown in horizontal crosshatch atits nominal position cantilevered from the rear side of the main cargobox. The interior of reference number 1514 is contiguous with that ofreference numbers 1510 and 1514. In FIG. 32, reference number 1515points to a side view of the forward portion of one of the two six-highstacks of 2×12 lumber boards. Each such board is 3.66 m L×3.81 cm H×28.6cm W and there are a total of twelve such boards in the stacked payloaddepicted in FIG. 32. The leading edge of these boards is located at FS68.6 cm, which is reference number 1506. The trailing edge of theseboards is at FS 434.3 cm, where the inside diameter of the cargoaxisymmetric fuselage pod is 78.44 cm and that trailing edge is shown tofit inside the extended cargo axisymmetric fuselage pod, which isnominally 61.0 cm longer than the standard AFP. In the standard sizedAFP, a payload of these same twelve boards would be limited to a boardlength of 3.05 m. Reference number 1516 points to a side view of the topor lid of the forward-most of the two 208.2 liter (55-gallon) drums thatare shown, with fine vertical crosshatch, laying end-to-end on theirsides as sample payload in a standard sized AFP. Each such drum is 87.6cm long and both are shown to be resting atop reference number 1517,which points to the payload latching rack that is pin-latched to the topsurface of the EPC and which is a truss-braced structure shown indiagonal crosshatch. Any of the several outsized payloads depicted inFIG. 32 can be attached to this latching rack. Reference number 1518points to a side view of a stack of commercial solar panels, positionedatop the reference number 1517 latching rack, that comprises a 54.9 cmtall stack of twelve such panels, each panel of which is 155.7 cm L×4.6cm H×104.65 cm W. The stack shown as reference number 1518 fits fullyinside the standard sized AFP. Reference number 1519 points to a sideview of a stack of seven sheets of plywood, each of which is 2.44 mL×2.86 cm H×1.22 m W shown with fine horizontal grain crosshatch andsitting atop the latching rack with the stack's trailing edge fittinginside of the dashed outline of the cargo axisymmetric fuselage pod. Theleading edge of this stack of plywood is at FS 145.5 cm where the insidediameter of the AFP is 131.45 cm. Its trailing edge is at FS 389.23 cmwhere the inside diameter of the cargo axisymmetric fuselage pod is131.45 cm. In FIG. 29, reference number 1520 points to a frontal view ofthe inner edge of the seat support bracket for the two-seat version ofthe SkyQart, showing its location and shape. In FIG. 30, referencenumber 1521 points to a frontal view of the diagonally crosshatched areathat represents flotation module #1, showing the extent of the spacethat it occupies in the forward portion of the rear hatch of the AFP. InFIG. 31, Reference number 1522 points to a frontal view of the outeredge of one of the two forward support brackets of the large centralMain Cargo Bin. Each of the two forward support brackets pin-latch ontothe innermost seat latching tracks of the EPC, which tracks enableadjustment of the latching position of the cargo bin support brackets asmay be needed to achieve a correct center of gravity for flight.Reference number 1523 points to a frontal view that shows the axiallocation inside the AFP of the extension cargo bins, which are depictedin horizontal crosshatch. Reference number 1524 points to a frontal viewof the large central Main Cargo Bin to show its size of 106.7 cm W×91.44cm H, showing its axial location inside the AFP. In FIG. 32, referencenumber 1525 points to a frontal view of the stack of seven sheets ofplywood, each of which is 28.58 mm thick, as the stack, shown in finelygrained horizontal crosshatch, sits atop the latching rack on the EPCinside the AFP. Reference number 1526 points to a frontal view of thestack of twelve solar panels, each of which is 45.72 mm thick, as thatstack, shown in coarse horizontal crosshatch, sits atop the latchingrack on the EPC inside the AFP. Reference number 1527 points to afrontal view of the circular outline depicting the end-on view of thesize and position of the 208.2 liter (55-gallon) drum payload as it sitsatop the latching rack on the EPC. Reference number 1528 points to afrontal view of the size and position of the two stacks of 2×12 lumber,with the side-by-side stacks each containing six boards and the stackstied or lashed onto the top of the latching rack on the EPC. In the topviews that follow, items are shown as transparent in order to depict thedetails of the underlying EPC. In FIG. 29, reference number 1529 pointsto a top view showing the forward edge of the front baggage compartmentand its projected size and location in the two-seat version of the EPCin the AFP. Reference number 1530 points to a top view of the 34.93 cmwide computer tablet that comprises the lid for that front baggagecompartment. Reference number 1531 points to a top view of the size andposition of the seat-bottom of the port side seat, shown in diagonalcrosshatch in a two-seat version of the EPC in the AFP. Reference number1532 points to a top view of the size and position of the headrest forthe port side seat, shown in diagonal crosshatch, in a two-seat versionof the EPC in the AFP. In FIG. 30, reference number 1533 points to a topview of the size and position of the midline front seat bottom, shown indiagonal crosshatch in a three-seat version of the EPC in the AFP.Reference number 1534 points to a top view of the size and position ofthe headrest for the midline front seat, shown in diagonal crosshatch ina three-seat version of the EPC in the AFP. Reference number 1535 pointsto a top view of the size and position of the seat bottom of the portside seat, shown in diagonal crosshatch in a three-seat version of theEPC in the AFP. Reference number 1536 points to a top view of the sizeand position of the headrest for the port side seat, shown in diagonalcrosshatch in a three-seat version of the EPC in the AFP. It can be seenthat this headrest extends aft of the rear hatchline. In FIG. 31,reference number 1537 points to a top view of the size and position ofthe front extension cargo bin, shown in medium horizontal crosshatch,with this bin attached to the front of the large central Main Cargo Bin.Reference number 1538 points to a top view of the forward port sidecorner of the large central Main Cargo Bin, shown as transparent and incoarse horizontal crosshatch on top of the EPC and revealing its sizeand position. Reference number 1539 points to a top view of the size andposition of the rear extension cargo bin, shown in medium horizontalcrosshatch, with this bin attached to the rear of the large central MainCargo Bin and fitting inside the space in the rear hatch vacated byflotation module #1. In FIG. 32, reference number 1540 shows a top viewof the forward portion of the aforementioned stack of lumber, shown intine grain and showing its size and position inside the cargoaxisymmetric fuselage pod. Reference number 1541 shows a top view of thesize and position of the stack of twelve solar panels shown in diagonalcrosshatch mounted on the EPC, wherein each such panel is 155.7 cmL×104.65 cm W. Reference number 1542 shows a top view of the edge of thehousing of the right hand solenoid-actuated latching pin that is fixedto the structure of the extension module for the cargo axisymmetricfuselage pod. Reference number 1542 has a matching mate that is the portside solenoid latching pin that is symmetrically placed on the oppositeside of the extension module. Reference number 1543 points to a top viewof the size and position of the stack of plywood, shown in coarsediagonal crosshatch, as it would be lashed inside the cargo axisymmetricfuselage pod. For clarity, the two 208.2-liter (55-gallon) drums aspayload are deliberately omitted from this top view drawing. Referencenumber 1544 points to a side view of the displaced rear hatchline, shownas a dashed vertical line, that is the trailing edge of the 61.0 cm Lcylindrical extension of the rear hatch of the AFP that creates thecargo axisymmetric fuselage pod. Reference number 1545 points to a sideview of the aft solenoid pin actuator that is standard equipment on theAFP extension piece. This aft solenoid pin actuator is located such thatit is 77.47 cm aft of the reference number 1546, which points to theintermediate solenoid pin actuator that is standard equipment on eachAFP and that is located 25.4 cm aft of the forward most solenoid pinactuator.

Robotic Delivery Cart (RDC)

FIGS. 33, 34, 35 and 36 depict a standard embodiment of the RoboticDelivery Cart (RDC), an important component to this invention. The RDCis an autonomous electric-powered cart that qualifies as a 40.2 km/hrNeighborhood Electric Vehicle and that is able to use residentialstreets and bike lanes to carry EPCs with their payload to neighborhooddestination doorsteps. It has its own solenoid latching pins that cansecurely pin-latch to a payload-laden EPC. It has a scissor jack belowthe deck surface of the RDC that allows it to adjust the height of itssurface from very low to as high as most commercial truck docks. Forpayloads consisting of two passengers, the RDC can be fitted with aretractable rain-roof. FIGS. 33, 34 and 35 show three views of the RDC,with transparent views to reveal underlying components explained wherenecessary. FIG. 34 shows the frontal view of the RDC, where suspensioncomponents are omitted for clarity in depicting the scissor jack. InFIG. 33, reference number 1600 points to a double arrow that depicts the106.7 cm dimension that is the full vertical range of travel of thesurface deck of the RDC achievable with its on-board scissor jack. Thetips of this double arrow point to the top surface of the RDC's surfacedeck in both its fully lifted and fully lowered positions. Referencenumber 1601 points to a side view of the center of the hinge bolt thatjoins the two arms of the scissor jack and comprises its central pivotaxis. This hinge bolt is shown in its position with the scissor jack inits fully extended up position that lifts the surface deck of the RDC toa 142.24 cm height above ground. As shown, each arm of the scissor jackis 159.18 cm long between centers of its end axles. Reference number1602 points to the end of a 1.22 m dashed line that depicts a side viewof the aft edge of the retractable windscreen/rain canopy with thecanopy in its forward windscreen position. The transparent flexibleplastic sheeting that comprises the surfaces of this windscreen/raincanopy can collapse into accordion-like folds. In rainy or dustyconditions, this reference number 1602 windscreen/rain canopy can beextended rearward, accordion-like, to provide an arched dome-likecovering to fully enclose the passenger-laden EPC. When so extended, thereference number 1602 dashed line moves to and fastens in a horizontalposition at the rear of the RDC as shown by reference number 1604 inFIG. 33. Alternatively, to make way for the loading and unloading of anEPC onto the front of the RDC, the bottom of the windscreen/rain canopymay be detached from the front of the RDC and folded, accordion-like, tothe rear of the RDC, as shown by reference number 1606. The entirewindscreen/rain canopy device attaches to the top of the solenoidmounting blocks on both sides of the RDC's surface deck and can bequickly and easily removed when appropriate. Reference number 1603points to a side view of the forward edge of the 10.16 cm talltrapezoidal-shaped forward solenoid mounting block that is fastened tothe side of the surface deck of the RDC. An identical rear solenoidmounting block is fastened to the side of the surface deck of the RDC ata position 77.47 cm aft of the forward block. These forward and rearsolenoid mounting blocks are matched by two identical such blocks thatare fastened symmetrically at the same fore-aft locations to theopposite side of the surface deck of the RDC. Reference number 1605points to a side view of the aft portion of the 8.89 cm H×205.74 cm Lbattery heavy-duty drawer slide rack, shown in coarse verticalcrosshatch, that is fastened to the underside of the surface deck of theRDC. This rack stiffens the surface deck and provides a sturdy set ofextensible battery drawer slides for loading and unloading spare SBPsonto the RDC. In FIG. 34, reference number 1607 points to a frontal viewof the upper outer corner of the port side solenoid mounting blockshowing its attachment to the side of the surface deck of the RDC.Reference number 1608 points to a frontal view of a diagonallycrosshatched outline of the Main Cargo Bin in its position mounted tothe surface of the EPC on four separate 10.16 cm tall latching legs.Showing through this crosshatched outline of the Main Cargo Bin are thedashed lines depicting the outline of two seats as would be carried onan EPC as an alternative payload to the Main Cargo Bin. Reference number1609 points to a frontal view of the interface of the underside of theRDC's surface deck with the 8.89 cm H×66.04 cm W space that is borderedon either side by heavy duty drawer slides and is normally dedicated tohauling SBPs. Reference number 1609 is shown with the RDC's surface deckpositioned such that its top surface is at its standard docking heightof 47 cm above ground level. Just below this interface is depicted thealternative, fully lowered position for this interface which is labeledas reference number 1633. When the 1633 interface of the RDC's surfacedeck and the SBP space below it are in this alternative, fully loweredposition, the RDC's surface deck is just 35.56 cm above ground level.This lowered position provides for easy off-loading of EPCs onto aspecialized ramp such as the one depicted as reference number 1632. Thisheight is the minimum height attainable for the RDC's surface deck. Itis from this 35.56 cm height that the specialized 1.22 m W standardoff-loading ramp, reference number 1632, can be used to off-load an EPConto street level. Reference number 1610 points to a frontal view of afinely crosshatched outline of one of the sheetmetal gussets thatstiffens the longitudinal right angle sheetmetal flange that carries theheavy-duty drawer slide on one side of the RDC. These drawer slides areof exactly the same dimensions as those used to carry the SBP inside theSkyQart. Reference number 1634 points to one of these longitudinal rightangle sheetmetal flanges, showing its size and position underneath thesurface deck of the RDC. Reference number 1611 points to the side of atop view of the shallow tire groove that guides the tires of the EPC onthe port side of the surface deck of the RDC. Reference number 1612points to the forward end of a finely diagonally crosshatched outlinethat represents the location of the left-hand 91 cm long linear actuatorfor the scissor jack of the RDC. This outline is shown with its lengthcommensurate with it being fully retracted, as occurs when the scissorjack is raised to its maximum height. An identical linear actuator isshown symmetrically located on the starboard side of the RDC and thesetwo actuators work in tandem to raise and lower the surface deck of theRDC by pulling or pushing on the lower scissor blade axles at the rearof the scissor blades. These blade axles, whose diameter is 12.7 mm,each holds a pair of 7.6 cm diameter by 3.18 cm wide cast polyurethanewheels, each of which has a wheel capacity is 272.2 kg. Reference number1613 points to a top view of the forward edge of the trapezoidal shapedsurface deck of an EPC, shown in coarse diagonal crosshatch, aspin-latched into its preferred position atop the RDC. Reference number1614 points to a top view of the forward edge of the diagonallycrosshatched surface deck of the RDC, showing it to extend over the topof the low-profile front suspension components of the RDC. Referencenumber 1700 points to the forward edge of a top (transparent) view ofthe 19.05 mm wide longitudinal heavy-duty drawer slide that is fastenedunder the port side of the RDC's surface deck. An identical drawer slideis shown symmetrically fastened under the starboard side of the RDC'ssurface deck. Reference number 1701 points to the middle portion of atop transparent view of the horizontally crosshatched outline of astandard battery pack, whose dimensions are 66.04 cm W×101.6 cm L, andit is shown in the position in which it is typically mounted onto theRDC's drawer slides. In FIG. 33, reference number 1615 points to adouble arrow whose 35.56 cm dimension indicates the height above streetlevel of the top of the surface deck of the RDC when in its fullylowered position. Reference number 1616 points to a side view of thebottom of the front tire of the RDC. Reference number 1617 points to aside view of the bottom edge of the stippled large triangular frontgusset that reinforces the attachment of the lower beam of the RDC toits front suspension pillar. Reference number 1618 points to a side viewof the center of the upper front bearing of the scissor jack, whichbearing is fastened by a gusset to the undersurface of the surface deckof the RDC and provides a pivot for one of the scissor jack's arms.Reference number 1619 points to a side view of the center of the rearcross-bolt of the ram of the linear actuator that actuates the scissorjack. Reference number 1620 points to the center of a side transparentview of the finely vertically hatched 5.08 cm H×50.80 cm L×50.80 cm Wnominal battery pack for the RDC. Reference number 1621 points to a sideview of the hub wheelmotor of one of the rear wheels of the RDC. In FIG.34, reference number 1622 points to a double arrow that depicts the 47cm height above ground level of the surface deck of the RDC whenpositioned for docking at a SkyNest. Reference number 1623 points to afrontal view of the position of the port side linear actuator on thefloor of the RDC. An identical starboard linear actuator is depicted inthe symmetrical position on the starboard side of the floor of the RDC.Reference number 1624 points to a transparent frontal view of the RDC's5.08 cm H×50.80 cm W swappable battery pack in its position submergedinto the bottom frame of the RDC. Reference number 1625 points to adouble arrow that indicates the 12.70 cm dimension that is the requiredground clearance of the RDC. Reference number 1626 points to a frontalview of the upper outer rear wheel of the starboard arm of the scissorjack. Note that this wheel is one of a pair that are mounted on eitherside of the rear end of the starboard scissor jack arm and that theyshare a common axle bolt. Two more identical wheels are symmetricallymounted on each side of the rear end of the port side scissor jack arm,sharing a common axle bolt. An identical pair of wheels are mounted oneither side of the rear ends of both the left and right lower scissorjack arms. Reference number 1627 points to a top view of the diagonallycrosshatched port side rear corner of the surface deck of the RDC.Reference number 1628 points to a top view of the trailing edge of theEPC shown pin-latched in its normal position atop the RDC. Referencenumber 1629 points to a top view of the finely diagonally hatched 5.08cm H×50.80 cm L×50.80 cm W battery pack of the RDC. Reference number1630 points to a side view of the recessed front headlight of the RDC.Reference number 1630 also depicts the position on the RDC where aremounted its DC fast-charging port and a suite of miniaturized equipmentrequired for street use including headlight, turn signal, small horn,forward looking camera, infrared sensors and LIDAR. These are allmounted outboard of the central space that is used for loading SBPs. Asimilar suite of required equipment including turn signals and brakelights is mounted on the rear of the RDC. Reference number 1631 pointsto a side view of the central pivot axis of the scissor jack (referencenumber 1601) except now shown in its fully lowered position. Referencenumber 1632 points to a side view of the 35.56 cm high speciallycontoured standard off-loading ramp for the RDC. Reference number 1633points to the interface of the RDC's surface deck with the below deckspace for an SBP, when positioned in its fully lowered position.Reference number 1635 points to a frontal view of the finely diagonallycrosshatched underslung transverse steel rod that serves as a bracebetween the central hinges of the left and right scissor jack blades.Reference number 1636 points to a top view of the finely horizontallycrosshatched 4.76 mm thick sheetmetal gusset that joints the left orport side rear horizontal and vertical frame members of the RDC. Anidentical gusset is shown in a symmetrical position on the starboardrear side of the RDC. Reference number 1637 points to one of the twosymmetrically placed 6.86 mm diameter latching pin receptacle holes inthe forward edge of the RDC's surface deck. These two receptacle holesstraddle the midline and are a nominal interoperable 81.28 cm apart. Aspecialized double-decker variant of the RDC is shown in FIG. 38, and ithas been modified to have a second set of heavy-duty drawer slidesattached on top of its surface deck. This second set of drawer slides,along with its scissor jack height adjustability, enable this doubledecker RDC to both on-load spent SBPs and off-load fully charged SBPs,allowing it to serve as a battery pack shuttle. Alternative embodimentsof the RDC may be used, including those of different size and capacity,provided that they interoperate with the other vehicles in the QUADsystem.

Dock Standards and Battery Swapping Standards

FIGS. 37 and 38 depict the dock standards and battery swapping standardsthat are two components important to this invention. FIG. 37 shows a topview and FIG. 38 shows a side view of an embodiment of the relevant dockequipment and their positions, with dimensions drawn to scale. Referencenumber 1700 points to a top view of the SBP's left side heavy-dutydrawer slide shown in its location inside of the battery charging rack.It can be seen that there is an identical drawer slide on the right sideof the SBP. Reference number 1701 points to a top view of the 66.04 cmW×101.60 cm L SBP as it fits inside the battery charging rack. Referencenumber 1702 points to a top view of the outer case enclosure of theleft-hand battery charging rack. It can be seen that there is anidentical right-hand battery charging rack shown in top view asreference number 1703, aligned symmetrically with reference number 1702in the upper portion of FIG. 37. The top views of the battery chargingracks that are labeled as reference numbers 1702 and 1703 are shown intheir positions relative to each other and to the central robot arm.Straight below in FIG. 38 and aligned with the FIG. 37 top view of thesebattery charging racks 1702 and 1703, is a side view of these racks thatshows each battery charging rack with its internal stack of five SBPs.These can be seen as the left and right battery charging racks depictedin the lower portion of FIG. 38, as part of the under-dock equipment atthe SkyNest. Reference number 1704 is shown in top view in FIG. 37 andin a side view in FIG. 38. It points to the square base plate of themulti-articulated robot arm. This base plate mounts the robot arm to thefloor of the service bay under the dock. In FIG. 37 reference number1705 points to a top view of the upper large extension arm of thebattery swapping robot, while in FIG. 38 it points to a side view ofthat extension arm. Reference number 1705 is attached to referencenumber 1706. Reference number 1706 points in FIG. 37 to a top view ofthe main vertical extension arm of the battery swapping robot, while inFIG. 38 it points to a side view of that vertical extension arm.Reference number 1707 points to a top view of the square plate thatserves as the gripping hand of the robot arm. This square plate can gripand move SBPs by using either the small suction cups along its edge,which are labeled as reference number 1708, or by use of its internalelectro-magnet's magnetic grip on objects that have ferrous surfaces.Reference number 1709 points to a side view of the nearly circular shapeof the opening of the rear hatch of the AFP, shown in its fully openedposition to be clear of the dock surface. Reference number 1710 pointsto a side view of the upper rear corner of the specialized gussetedright-angle sheetmetal flange that is mounted onto the top surface deckof the specially modified double-decker RDC. This gusseted right-anglesheetmetal flange is shown in coarse vertical crosshatch. Except forbeing mounted upside down, this flange is identical to the one shown inFIG. 34 mounted onto the undersurface of the surface deck of the RDC asreference number 1634. This up-side down flange (1710) is one of a pairof such flanges that are 205.74 cm L×8.89 cm H and these flanges are66.04 cm apart. Each such flange has centered and securely mounted ontoits inner face a full 205.74 cm length of the standard 19.05 mm W×76.2mm H heavy duty drawer slides that fit the SBP. The stiffness of thesesheetmetal flanges is reinforced with a series of sheetmetal gussets,one of which is shown as reference number 1610 in FIG. 34. These upperfull-length drawer slides are depicted in FIG. 38 as being 205.74 cmlong and are shown in a side view with fine diagonal crosshatch. Theseupper drawer slides are identical to that shown as reference number1711, which is a side view of an identical diagonally crosshatchedfull-length SBP drawer slide that is attached to and centered on theinner face of the lower gusseted right angle sheetmetal flange that isattached to the underside of the standard RDC's surface deck. This RDCis shown docked at the street-side edge of the SkyNest dock and thetires of the RDC can be seen to be resting on the street surface.Reference number 1712 points to a downward vertical arrow whose tipindicates the exact plane of the interface between the street-side edgeof the SkyNest dock and the front surface of the RDC that is dockedthere. At the tip of arrow 1712, it can be seen that the top surface ofthe deck of the RDC is the standard 47 cm above street level and this isexactly the height that makes it flushly aligned with the top surface ofthe street-side edge of the SkyNest dock. Reference number 1713 pointsto a jagged edge of a gap shown in the SkyNest dock surface, whichindicates an imaginary separation distance between the dock portionoverlying the service bay for battery swapping and the dock portion thatborders on the street level where RDCs await loading. This gap isactually 4.36 m in order to provide the 7.47 m standard dock width atall SkyNests for the bi-directional movement of passengers thatpreserves social distancing, and for bidirectional movements of EPCs.Reference number 1714 points to a side view of the segment of heavy-dutybattery drawer slides under the dock surface on the street side of theservice bay. The purpose of this segment and that opposite drawer slidesegment depicted by reference number 1720 on the other side of theservice bay, is to leave a gap in the drawer slides above the robot armso that the arm can pull and fully remove SBPs from the under-dockdrawer slides. By so removing SBPs, the robot arm can more quickly movethem in 3D into and out of the slots in the battery charging rack andthe SkyQart. Reference number 1715 points to a side view of a dashedoutline of a 184.15 cm long segment of drawer slide that is normallyabsent but that can be inserted as an accessory into the gaps betweenthe segments in the under-dock drawer slides so as to effectively createa continuous pair of drawer slides that extend all the way from theSkyQart side of the dock 7.47 m to the street side of the dock. Theinsertion of reference number 1715 to enable manual movement of SBPsunder the dock to and from docked SkyQarts and RDCs occurs only in thoseinstances when the robot arm and battery charging rack are eitherinoperative, disabled or otherwise unavailable. Reference number 1716points to a side view of the edge of a sturdy vertical pillar thatsupports the street side edge of the SkyNest dock. Reference number 1717points to a side view of an SBP that is stored in the bottommost of thefive slots of the left-hand battery charging rack. There are five suchSBPs stored in each battery charging rack shown in a side view in FIG.38. Reference number 1718 points to a side view of the bottom of theleft-hand drawer slide of an SBP that is stored in one of the slots ofthe battery charging rack. Reference number 1719 points to a side viewof the distal extension arm of the battery swapping robot, showing itssliding attachment to reference number 1705, the robot's upper largeextension arm. Reference number 1720 points to a side view of thesegment of the under-dock battery drawer slide on the SkyQart side ofthe dock, depicting its 45.72 cm extension into the under-dock area fromthe SkyQart side edge of the dock. Reference number 1721 points to aside view of the edge of a sturdy vertical pillar that supports the docksurface at the edge of the SkyQart side of the dock. Reference number1722 points to a side view of the dashed line that represents the rearhatchline of the SkyQart, which during docking is positioned inapposition to the SkyQart side of the dock, as shown in FIG. 38.Reference number 1723 points to a side view of the forward edge of theSBP as it is normally positioned inside the SkyQart. Reference number1724 points to a side view of the paved parking surface that is 47 cmbelow the dock surface at the SkyQart side of the dock. Reference number1725 points to a side view of the battery swapping robot's centralrotating turret. Reference number 1706 points to a side view of the mainvertical extension arm of the battery swapping robot. Reference number1727 points to a side view of one of the small carts that support andallow movement of the battery charging rack that it supports. Normally,these carts are securely locked in place. Reference number 1728 pointsto the bottom of a side view of the horizontally crosshatched oval thatrepresents the SkyQart's portion of the DC fast-charging port that mateswith and connects to the dock's DC fast-charging port in cases wherebattery swapping is not in use. Reference number 1729 points to a sideview of the bottom of the forward edge of the 99.06 cm L×7.62 cm H×1.91cm W battery drawer slide that holds the SBP into the belly of theSkyQart. The other components depicted for perspective in FIG. 38include dashed line outlines of the SkyQart's AFP, main landing gear andwheel fairing, monostrut, nacelle and propeller as well as apassenger-laden EPC that is pin-latched onto the top of the RDC. The RDCis shown with its scissor jack adjusted to position the top of the RDC'ssurface deck at 47 cm above street level. Note that the main landinggear and wheel fairing nest under the dock during docking and batteryswap. Alternative embodiments of the QUAD dock, including those ofdifferent dimensions and facilities, are possible provided that theyinteroperate with the other vehicles of the QUAD system.

Graph of Tolerable Jerk Rate on Take-Off

FIG. 39 depicts a graph of the motion of the SkyQart on take-off. Therate at which SkyQart acceleration increases during the take-off rolland decreases during landing roll can only be as high as will betolerable to the public fare-paying passenger. The graph in FIG. 39depicts the range of those accelerations for take-off and the relatedparameters of motion. The rise and fall of acceleration rates used tomodel the trajectories of the SkyQart in its standard operations at theSkyNest are called the jerk rates and these are derived from the jerklimits adopted by the industry for amusement park rides. The limit forchanges in acceleration used in these models is a modest jerk rate of3.4 m/sec³. All movements conducted by vehicles in the QUAD system,whether in accelerating or decelerating and whether by SkyQart, EPC orRDC, are constrained at or below the jerk rate of ±3.4 m/sec³. Thisconstraint model for movement is herein named guided rate accelerationchange execution or GRACE. The take-off performance modeled in FIG. 39is the maximum performance expected during conditions of no wind and drypavement. Such maximum performance is expected to be routine andconsistent at all SkyNests and provides the metrics for sizing ofSkyNests. In FIG. 39 reference number 1800 points to the dashed linedepicting the jerk rate during take-off acceleration. This dashed linecan be seen to rise rapidly from brake release at time zero to its peakvalue of 3.2 m/sec³. Reference number 1800 (the jerk rate) can be seento remain at this tolerable peak as the acceleration curve, labeled asreference number 1801, increases steadily until it reaches 0.8 G.Reference number 1802 points the tip of its arrow to the point on theaircraft velocity curve where the velocity reaches the SkyQart's liftoffspeed of 24 m/sec in 4.34 seconds in a distance of 38.7 m. Referencenumber 1803 points the tip of its arrow at the point on the take-offdistance curve at 4.34 seconds where it reaches a distance of 38.7 m.

The Standard Swappable Battery Pack (SBP)

FIGS. 40, 41, 42 and 43 together depict an embodiment of the standardswappable battery pack (SBP). The SBP is an important component to thisinvention in order to provide a uniformly sized, high-quality energystorage device with standardized voltage and connections. It is used inall of the SkyQart aircraft and is made to be quickly swappable andrapidly recharged. It has definable specifications and is drawn to scalein FIGS. 40, 41, 42 and 43, which show its external components infrontal, aft, top and side views. In FIG. 40, reference number 1900points to a frontal view of the male component of the 1.9 cm wideheavy-duty drawer slide on the side of the SBP, showing its position ofattachment to the container of the SBP. Reference number 1901 points toa frontal view of the lower corner of the stainless steel sheetmetalcontainer of the SBP. Reference number 1902 points to a frontal view ofthe large “+” or positive battery terminal on the right side of theforward face of the SBP. Reference number 1903 points to a frontal viewof the center of the starboard cooling port, one of the two coolingports of the SBP. Reference number 1904 points to a frontal view of theaft face of the SBP. Reference number 1905 points to a frontal view ofthe midline 3.8 cm diameter smoke vent on the aft face of the SBP. InFIG. 42, reference number 1906 points to a top view of the heavy-dutydrawer slide on the port side of the SBP. Reference number 1907 pointsto a top view of the outline of the container of the SBP. In FIG. 42,reference number 1908 points to a top view of the heavy-duty drawerslide on the starboard side of the SBP. In FIG. 43, reference number1909 points to a side view of the aft face of the container of the SBP.In FIG. 43, reference number 1908 also points to a side view of the 7.6cm tall heavy-duty drawer slide on the starboard side of the long edgeof the SBP. In FIG. 40, reference number 1911 points to a frontal viewof the large “−” or negative battery terminal on the port side of theforward face of the SBP. Reference number 1912 points to a frontal viewof the midline five electrical terminal, grommeted battery managementsystem port on the forward face of the SBP. In FIG. 42, reference number1911 also points to a top view of the recessed “−” or negative batteryterminal of the port side of the forward face of the SBP. Referencenumber 1914 points to a top view of the port side cooling port on theforward face of the SBP. Reference number 1912 also points to a top viewof the midline grommeted battery management system port on the forwardface of the SBP. Reference number 1903 also points to a top view of thestarboard cooling port on the forward face of the SBP. Reference number1902 also points to a top view of the recessed “+” or positive batteryterminal of the right side of the forward face of the SBP. Alternativeembodiments of the SBP are possible, and may be adopted by standardsorganizations in the future, while the standard embodiment of the SBPpresented herein is expressly sized to be compatible with the SkyQartsof the QUAD system.

The Crash Cushion

FIGS. 44 and 45 depict the QUAD crash cushion. The crash cushion is animportant component to this invention. It a moveable train of cushionedcarts placed at the end of the SkyNest's active runway pavement tosafely bring to a stop an out-of-control SkyQart. The calculation of theimpact forces and deflections of the crash cushion have been provided inthe foregoing. The components of the crash cushion are shown in FIGS. 44and 45 as items labeled by reference number and are drawn to scale. Thetrain of crash cushion carts shown in FIG. 44 is shown at 0.4 times thescale of the FIG. 45 view of the crash cushion cart. Reference number2000 points to a top view of one of the large elastic bungee bands thatjoins two crash cushion carts together through steel attachment rungsand helps keep the carts upright during a skid. Reference number 2001points to a top view of the outline of the rectangular rubber footpad,shown in vertical crosshatch on the undersurface of the lower plate ofthe crash cushion cart's rear steel brace in its down or extendedposition. Reference number 2002 points to a top view of one of thenominal 10.16 cm diameter circular steel rungs that aligns and holds thenominal 223.52 cm long large caliber elastic bungee band across the rearjunction of two crash cushion carts. There are four such rungs on thebackside of each crash cushion cart and each of these rungs is weldedonto the vertical rear steel wall of the crash cushion. Reference number2003 points to a top view of the rear edge of the vertical steel wallthat makes up the backside of the crash cushion cart. Reference number2004 points to a top view of the large airbag that occupies the majorityof volume on the crash cushion cart. Reference number 2005 points to atop view of the castoring starboard front tire of the crash cushioncart. A paired identical castoring front tire is also shown on the portside of the crash cushion cart. Reference number 2006 points to a topview of the nominal 50.8 mm diameter rear plastic mast on which thememory foam beanbag is suspended. There are two such masts, one rear andone front, and they are placed nominally 86.36 cm deep to the impactsurface of the beanbags so that there will be 36.36 cm of compressionand deceleration before the impacting vehicle reaches these frangiblemasts. Reference number 2007 points to a top view of the wall of memoryfoam beanbags. Reference number 2008 points to a top view of one of the0.254 mm flexible load-spreading polyethylene terephthalate (PET) tarpswhose tensile strength is 55 Mpa and whose peripheral edges are securedwith aramid fiber straps to the impact side of the wall of beanbags oneither side of the junction between any two crash cushion carts.Reference number 2007 also points to a side view of the memory foambeanbag wall, which provides the impact side of the crash cushion cart.Reference number 2006 points to a side view of the top of the 50.8 mmdiameter frangible plastic mast from which the beanbags are suspended.There are two such masts on each crash cushion cart, one of which islocated at the front edge and the other at the rear edge of the cart.Reference number 2004 also points to a side view of the large airbag.Reference number 2003 also points to a side view of the top portion ofthe steel rear wall of the crash cushion cart. Reference number 2002also points to a side view of one of the 10.16 cm diameter steel rungsthat align and fasten the large caliber elastic bungee bands to the rearwall of the crash cushion cart. Reference number 2014 points to a doubleended arrow of 1.5 m nominal length that depicts a nominal distance ofthe compression of the crash cushion cart's cushioning materials in thecase of a 20 m/sec SkyQart collision with the cart. Reference number2015 points to a side view of a heavy dashed line that depicts thehinged upper rear steel retractable brace in its retracted position. Itsattached steel hinge is shown at the bottom of this heavy dashed line.Reference number 2016 also points to a side view of the rectangularrubber footpad that is attached to the underside of the hinged lowerrear steel retractable brace shown in its retracted position. Referencenumber 2015 also points to a side view of a heavy solid line thatdepicts the hinged upper rear steel retractable brace in its down orextended position where it serves as a diagonal brace for the lower rearsteel retractable brace. Reference number 2001 points to a side view ofthe rectangular rubber footpad that is attached to the underside of thehinged lower rear steel retractable brace shown in its down or extendedposition, which places the footpad onto the pavement. Reference number2019 points to a side view of the hinged lower rear steel retractablebrace shown in its down or extended position. Reference number 2020points to a side view of a projection of the port side rear tire of thecrash cushion cart. This tire as shown is 25.4 cm wide by 40.64 cm talland provides 5.08 cm of ground clearance for the crash cushion cart.Reference number 2021 points to a side view of the nominal 17.78 cm tallsteel ladder frame that forms the bottom of the crash cushion cart.Reference number 2022 points to a side view of the hinged steel rampthat supports the beanbag wall and eases the collision of the nosewheelof the SkyQart with the crash cushion cart. Reference number 2023 pointsto a side view of the tip of the nose of the AFP of the SkyQart.Reference number 227 points to a side view of the bottom of the nosetire of the SkyQart. Reference number 2025 points to a side view of the12.7 mm diameter steel bolt that rigidly attaches the hinged upper rearsteel retractable brace to the hinged lower rear steel retractablebrace. Reference number 2019 also points to a side view of the hingedlower rear steel retractable brace, shown as a dotted line in itsretracted position on the backside of the crash cushion cart. Referencenumber 2027 points to a side view of the hinge that joins the hingedlower rear steel retractable brace to the steel rear wall of the crashcushion cart. Reference number 2028 points to a side view of thetriangular steel gusset that joins the bottom of the steel rear wall ofthe crash cushion cart to the steel ladder frame of the crash cushioncart. Reference number 2029 points to a side view of the hinge of thesloped ramp made of a steel plate. Reference number 2030 points to aside view of a heavy dashed line that depicts this sloped steel ramp inits up or retracted position as would occur during re-location of thecrash cushion cart. The exact dimensions, cushions and weights providedfor this embodiment of the crash cushion cart system may vary in otherembodiments that still conform to this crash cushion concept andprocess.

The entirety of the following references are hereby incorporated byreference herein:

-   ¹https://ww2.arb.ca.gov/sites/default/files/classic/enf/advs/advs369.pdf    California's neighborhood electric vehicle regulations in detail.-   ²    https://incompliancemag.com/article/incorporating-lightning-protection-into-vtol-and-hybrid-propulsion-vehicle-designs/    The description of integrating lightning protection into electric    aircraft.-   ³https://www.ezwoodshop.com/lumber-dimensions.html The description    of the dimensions of standard lumber.-   ⁴http://donsnotes.com/reference/size-humans.html The standards for    size for humans.-   ⁵https://ems.stryker.com/en/ambulance-cots A Stryker litter is    204.47 cm L×58.42 cm W and will fit onto the EPC if slid forward    maximally, and if a slight carve out is made into the rear hatch.    The litter collapses down to 160.02 cm L which helps it to fit onto    the EPC.-   ⁶http://payload.eaa62.org/technotes/tail.htm The formulae for    calculating tail volumes.-   ⁷https://www.mcmaster.com/6603a33 The heavy duty drawer slide type    used for mounting the SBP, with 272.16 kg capacity per pair.-   ⁸https://www.ncbi.nlm.nih.gov/pmc/articles/PMC543775I/ The adverse    health effects of noise. WHO recommends 45 dB L_(den) as the    exposure limit.-   ⁹https://payload.nps.gov/asis/planyourvisit/upload/campgroundregs2013-2.pdf    The US National Park noise limits for generators which limit    generator noise to no more than 60 dBA at a 15.24 m sideline. That    is equivalent to 51.6 dB at a 40 meter sideline.-   ¹⁰https://payload.wcc.nres.usda.gov/climate/windrose.html The    official US data for local prevailing winds and wind rose    orientation.-   ¹¹http://www.euronoise2018.eu/docs/papers/449_Euronoise2018.pdf The    description and specification of the poro-elastic road surface.-   ¹²http://physicstasks.eu/1984/braking-vehicle The explanation of    acceleration down or up a ramp.-   ¹³https://payload.raisedfloor.co.uk/work/multi-storey-car-park-constructed-luton-airport/    The engineering guide for steel beam construction of stadium like    structures.-   ¹⁴http://www.dtic.mil/dtic/tr/fulltext/u2/a801336.pdf This paper by    Hicks and Hubbard in 1947 confirms that a 7-bladed prop turning    slowly results in reduced noise, and that the noise of seven blade    prop of adequate take-off thrust can be no more than 35 dBA of noise    at a 40 m sideline.-   ¹⁵https://payload.amazon.com/Pack-Non-Marking-Soft-Tread-Polyurethane-Casters/dp/B011RDY7O6    The tire for the EPC is 12.7 cm diameter×3.175 cm wide as a    non-marking, soft caster type with 204.12 kg capacity.-   ¹⁶https://payload.tlxtech.com/solenoids/one-inch-stroke-shot-bolt-solenoid    An example of a sturdy solenoid with a 2.54 cm stroke.-   ¹⁷https://us.sunpower.com/solar-resources/sunpower®-x-series-residential-dc-x22-370    The specifications for the SunPower solar panels as 22.7% efficiency    with 370 watts and dimensions of 155.7 cm×104.65 cm×4.572 cm at 18.6    kg.-   ¹⁸https://payload.rwmcasters.com/products/wheels/urethane-on-iron-wheels/    The scissor jack for the RDC uses tires that are 7.62 cm diameter    and 3.175 cm wide as high capacity cast polyurethane wheels on 12.7    mm axles from a source above. Each can accommodate a 272.16 kg load.-   ¹⁹https://payload.bluegiant.com/Files/Architects/Loading-dock-System-Guide.aspx    Given on page 3 of this weblink are the range of specifications and    standards for commercial truck docks.-   ²⁰https://www.grainger.com/product/GRArNGER-APPROVED-12-Light-Medium-Duty-Sawtooth-1NWV1    An example of a tire suitable for the RDC: 30.48 cm OD and with    11.43 cm hub width, this tire is 9.21 cm wide and specified as a    4.10/3.5-6 tire.-   ²¹https://pushevs.com/2017/03/20/tesla-leapfrog-competition/ The    energy density by volume for the current Tesla car batteries.-   ²²http://www.bsharp.org/physics/skidmarks The physics of skidding.-   ²³https://www.amazon.com/Chill-Sack-Bag-Furniture-Charcoal/dp/B00P21UAHK/ref=asc_dfB00P21UAHK/?tag=hyprod-20&linkCode=df0&hvadid=192245446453&hvpos=&hvnetw=g&hvrand=10251932198627587180&    hvpone=&hvptwo=&hvqmt=&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=9032308&h    An example of a large memory foam beanbag.-   ²⁴https://www.bigairbag.com/revolution/ An example of the large    inflatable airbag with customizable internal baffles, external vent    windows, internal blowers and anchoring system, that can be used on    the crash cushion cart.-   ²⁵http://onlinepubs.trb.org/Onlinepubs/nchrp/nchrp_rpt_157.pdf A    1975 Goodyear study of crash impact tolerances.-   ²⁶http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.212.5449&rep=rep1&type=pdfA    comprehensive paper on crash impact analysis and human tolerances.-   ²⁷https://pdfs.semanticscholar.org/269d/34eeb08f2de3a2d30f4db4bb10a43f6053fb.pdf    This paper compares several types of linear shock absorber and    motion control devices useful for the active main landing gear.-   ²⁸http://www.laserguidance.com/landing_z.html A description of a    laser guidance system for landing.

What is claimed is:
 1. An ultra-quiet, multi-modal, on-demand passengerand cargo transportation system comprising: a) a plurality of very smallairports herein named SkyNests, each comprising: i) an occupied areawithin a perimeter that is no larger than 5 ha; and ii) a dock facilitycomprising docking stations; and iii) autonomous robotic electricpayload carts configured to latch onto and haul a payload of passengersor cargo along said dock facility to and from said plurality of dockingstations at said SkyNests; and wherein for noise reduction, a pluralityof SkyQarts, each of which is an ultra-quiet electric-powered aircraftconfigured to operate at said SkyNest, and wherein said SkyNest isconfigured for flight operations conducted by ultra-quietelectric-powered aircraft that are configured to haul to and from saidplurality of docking stations said payload of passengers or cargo thatis latched onto one of the electric payload carts; and wherein acommunity noise level impact of flight operations along said perimeterof said SkyNest is maintained below 55 dBA LA_(eq), 5 s.
 2. Theultra-quiet, multi-modal, on-demand passenger and cargo transportationsystem of claim 1, comprising a paved surface for take-off and landinghaving a length no longer than 200 m.
 3. The ultra-quiet, multi-modal,on-demand passenger and cargo transportation system of claim 2, furthercomprising a paved surface heater to heat said paved surface and preventicing of said paved surface.
 4. The ultra-quiet, multi-modal, on-demandpassenger and cargo transportation system of claim 2, wherein said pavedsurface for take-off and landing comprises a poro-elastic road surface(PERS) configured to reduce tire noise.
 5. The ultra-quiet, multi-modal,on-demand passenger and cargo transportation system of claim 1, furthercomprising an energy-absorbing crash cushion configured at an end ofsaid paved surface.
 6. The ultra-quiet, multi-modal, on-demand passengerand cargo transportation system of claim 1, further comprising a fencethat is at least 2 m tall and configured around said perimeter of saidSkyNest.
 7. The ultra-quiet, multi-modal, on-demand passenger and cargotransportation system of claim 1, wherein for noise reduction, saidplurality of SkyQarts take off from the paved surface and then climbsout along a curved traffic pattern having a radius of curvature of atleast 94 m (308.4 ft); and wherein, for noise reduction, said pluralityof SkyQarts land onto the paved surface after descending along a curvedtraffic pattern having a radius of curvature of at least 94 m (308.4ft).
 8. The ultra-quiet, multi-modal, on-demand passenger and cargotransportation system of claim 1, further comprising a robotic deliverycart, and wherein the robotic delivery cart comprises a scissor jackthat is configured to move said surface deck of said robotic deliverycart up and down to on-load or off-load an electric payload cart; and atruck docking station that comprises a commercial truck dock or a truckbed at which said robotic delivery cart can use said scissor jack tomove said surface deck to align with the commercial truck dock or truckbed.
 9. The ultra-quiet, multi-modal, on-demand passenger and cargotransportation system of claim 8, wherein the dock facility comprising:a dock battery charging station comprising: a battery charger; and arobot arm to autonomously robotically interchange said charged batterywith a depleted battery from one of said plurality of SkyQarts.
 10. Theultra-quiet, multi-modal, on-demand passenger and cargo transportationsystem of claim 1, wherein the SkyNests comprises adjacent aircraftdocking stations at which a first SkyQart of the plurality of SkyQartshaving wingtips that tilt upward and a second SkyQart of the pluralityof SkyQarts having wingtips that tilt downward are docked, wherein saidadjacent aircraft docking stations are spaced a distance to receive thefirst and the second SkyQarts with overlapping wingtip configurations,wherein at a first aircraft docking station, said first SkyQart isdocked and wherein at a second and adjacent aircraft docking station tosaid first aircraft docking station, said second SkyQart is docked; andwherein the distance between the first and second aircraft dockingstations would not accommodate simultaneous docking of SkyQarts with thesame wingtip configuration.
 11. An ultra-quiet, multi-modal, on-demandpassenger and cargo transportation system comprising: a) a plurality ofvery small airports herein named SkyNests, each comprising: i) anoccupied area within a perimeter that is no larger than 5 ha; andwherein said SkyNest is configured for flight operations conducted byultra-quiet electric-powered aircraft, herein named SkyQarts, that areconfigured to haul to and from said docking stations said payload ofpassengers or cargo that is latched onto one of the electric payloadcarts; and ii) a dock facility having docking stations; wherein acommunity noise level impact of flight operations along said perimeterof said SkyNest is maintained below 55 dBA LA_(eq), 5 s; b) autonomousrobotic electric payload carts configured to latch onto and haul apayload of passengers or cargo along a dock surface of said dockfacility to and from said docking stations, c) electric poweredautonomous robotic delivery carts, each comprising a surface deck; andwherein each of the plurality of autonomous robotic delivery carts areconfigured to haul one of said autonomous robotic electric payload cartson said surface deck, wherein the autonomous robotic electric payloadcart autonomously docks and latches onto said surface deck of theautonomous robotic delivery cart with a piggyback transportationfunction; and d) each of said SkyQarts comprising: a cabin; and a cabinfloor, wherein each of the SkyQarts is configured to haul one or moreautonomous robotic electric payload carts and take-off and land withsaid autonomous robotic electric payload carts therein; and wherein eachof the autonomous robotic electric payload carts is configured toautonomously dock and latch into said cabin of the SkyQart.
 12. Theultra-quiet, multi-modal, on-demand passenger and cargo transportationsystem of claim 11, wherein said docking station has a dock height andwherein the said dock height and a height of said surface deck of saidautonomous robotic delivery cart and a height of said cabin floor of anyone of the SkyQarts are substantially the same, within ±2 mm or less;and wherein said autonomous robotic delivery carts are autonomous havingan autonomous control system to control docking of said autonomousrobotic delivery cart to one of said SkyQarts with a positionalprecision of ±2.0 mm or less; and wherein each of the said SkyQarts hasa hatch that opens to provide access for docking of an autonomousrobotic delivery cart to deliver or remove an autonomous roboticelectric payload cart into or from the SkyQart's cabin by rolling saidautonomous robotic electric payload cart from the surface deck of theautonomous robotic delivery cart onto said cabin floor and vice-versa;and wherein the autonomous robotic delivery carts each have a precisionpositioning system to control docking of said autonomous roboticdelivery cart to said SkyQart or to said cart docking station at a dockwith a positional precision of ±2.0 mm; and wherein said autonomousrobotic delivery cart is automatically controlled to deliver anautonomous robotic electric payload cart to a dock from a station orfrom a dock to a station; and wherein said station is a home, a place ofbusiness, a truck dock, truck or other vehicle or a bus stop.
 13. Theultra-quiet, multi-modal, on-demand passenger and cargo transportationsystem of claim 12, wherein the payload comprises at least onepassenger.
 14. The ultra-quiet, multi-modal, on-demand passenger andcargo transportation system of claim 13, wherein said surface deck ofthe autonomous robotic electric payload cart has a seat-track latchingsystem configured to latch a passenger seat thereto.
 15. Theultra-quiet, multi-modal, on-demand passenger and cargo transportationsystem of claim 14, wherein the autonomous robotic electric payloadcarts are configured to roll on the surface deck of the autonomousrobotic delivery carts and wherein said autonomous robotic electricpayload cart comprises a latch sensor that detects when said electricpayload cart is securely latched to said autonomous robotic deliverycart.
 16. The ultra-quiet, multi-modal, on-demand passenger and cargotransportation system of claim 15, wherein the plurality of autonomousrobotic delivery cart comprises a scissor jack to change a height of itssurface deck for docking and loading or unloading of one of theautonomous robotic electric payload carts.
 16. An ultra-quiet,multi-modal, on-demand passenger and cargo transportation systemcomprising: a) a plurality of very small airports herein named SkyNests,each comprising: i) a paved surface for take-off and landing having alength no longer than 200 m; and ii) an occupied area within a perimeterthat is no larger than 5 ha; and iii) a dock facility comprising dockingstations for electric-powered land and air vehicles; and wherein saidSkyNest is configured for flight operations conducted by ultra-quietelectric-powered aircraft, herein named SkyQarts, that are configured tohaul to and from said docking stations said payload of passengers orcargo that is latched onto one of the electric payload carts; andwherein a community noise level impact of flight operations along saidperimeter of said SkyNest is maintained below 55 dBA LA_(eq), 5 s; b)autonomous robotic electric payload carts configured to latch onto andhaul a payload of passengers or cargo along said dock facility to andfrom said docking stations; c) a plurality of autonomous roboticelectric-powered aircraft, each of which being named a SkyQart and eachcomprising: i) an on-board electrical power source; ii) a propulsor thatis driven by an electric motor that is powered by said on-board electricpower source; iii) a payload capacity of at least 120 kg; and iv) atake-off and landing distance on a horizontal surface of less than 60 mat sea level in zero wind; and v) a quiet take-off, wherein take-offfrom a horizontal surface produces a noise of no more than 55 dBA LAeq,5 s as measured at a 40 m sideline distance along the azimuth of maximumnoise from an unobstructed vantage at a height of 1 m above saidhorizontal surface; wherein each of said SkyQarts comprises a fuselagewith an interior cabin therein and an interior cabin floor; and whereineach SkyQart is configured to haul one of said autonomous roboticelectric payload carts within said cabin and to take-off from a firstSkyNest and land at a second SkyNest with said autonomous roboticelectric payload cart in the cabin.
 17. The ultra-quiet, multi-modal,on-demand passenger and cargo transportation system of claim 16, whereineach SkyQart comprises: a) a propeller that is driven by an electricmotor, herein called a propeller motor, wherein the propeller is anultra-quiet propeller comprising: i) at least three blades; and ii) adiameter of at least 1.83M; and wherein said ultra-quiet propellermaintains a propeller blade tip speed of less than 152.4 m/sec; and b) atrailing edge wing flaps system wherein said wing flaps areultra-fast-acting, herein called fast flaps, and wherein to enable shortlandings, said fast flaps can be fully retracted in less than 0.5seconds from a fully extended position.
 18. The ultra-quiet,multi-modal, on-demand passenger and cargo transportation system ofclaim 17, wherein a wheelie on take-off is prevented by a combination ofcomponents on each SkyQart, comprising: said propeller whose thrust axisis at least 60 cm or more above a center of gravity of said SkyQart; andwherein said on-board electrical power source comprises a swappablebattery pack having a mass, and wherein said standard battery pack islocated below the cabin floor of the axisymmetric fuselage pod in orderto apply a downward force that helps prevent a wheelie; and wherein anactive main landing gear is configured to rotate the main landing gearleg upward when the indicated airspeed becomes a lift-off speed of 24m/sec so as to increase the fuselage pitch angle during take-off inorder to increase wing lift and thereby induce lift-off; and wherein awing having extended wing flaps during take-off produces a nose-downpitching moment that prevents wheelies by keeping the nose tire on thepavement during take-off; and wherein a forward location of the nosetire extends the wheelbase and moves the center of gravity forward toincrease weight on the nose tire; and wherein a horizontal tailcoefficient is large enough with said forward location of said SkyQart'scenter of gravity to induce a nose-up lift-off when the indicatedairspeed becomes a lift-off speed of 24 m/sec; and wherein an autonomouscontrol system that has a sensor for fuselage pitch angle detects theonset of a wheelie and modulates the thrust of the main landing geartires in order to prevent said wheelie.
 19. The ultra-quiet,multi-modal, on-demand passenger and cargo transportation system ofclaim 16, wherein said SkyQart comprises an empennage with a twin boomconfiguration comprising two separate vertical tail surfaces whoselaminar flow airfoil is structurally attached to an aft portion of itsrespective tailcone; and wherein a fixed horizontal tail surface has alaminar flow airfoil and has its tips span between and structurallyattached at the top of the twin vertical tail surfaces and wherein saidhorizontal tail surface has a moveable elevator control surfacecomprising its trailing edge; and wherein two separate fixed verticaltail surfaces, one port and one starboard, each of which is structurallyattached to the rear portion of a port and a starboard tailcone,respectively, and each of which has a moveable rudder control surfacecomprising its trailing edge.